Nichole Bloom and Fabienne Therese in "Teenage Cocktail"

“We’re going to get in some trouble,” coos Jules (Fabienne Therese), just before heading out to a party that would make Caligula blush in “Teenage Cocktail.” Adds her recently acquired BFF Annie (Nichole Bloom), “I hope so.”

It wasn’t always this way, but the two become fast friends in John Carchietta’s cooly calibrated thriller in which Annie, a shy young woman in the midst of her senior year at Rochelle High, is swept up in the wiles of her far more confident classmate Jules, a relationship so beguiling that it hurts all the more when it starts to go bad. With dreams of heading to New York to start anew, Jules lets Annie in on her secret way of earning some extra cash, webcamming for strangers, though showing no more than she would during an average day at school. Yet when one of those watching (Pat Healy) extends a potentially lucrative offer for an in-person date, the girls realize they may have gotten in over their head.

Despite Carchietta’s background in horror, “Teenage Cocktail” is a different beast altogether, eliciting all the feels as Annie and Jules create a cocoon for themselves as they fall fast for each other, with their milkshake meet-ups and a sleek, synthy score underlining the purity of their connection. However, when that cocoon is ultimately pierced, the co-writer/director doesn’t skimp on what he’s learned from previous productions, using the intoxicating chemistry between Therese and Bloom to give resonance to how cruel it is when Annie and Jules’ aspirations run into harsh reality. True to its title as a mix of elements that goes down smooth, “Teenage Cocktail” represents a big step forward for the filmmaker, one that was quite welcome as he explained to me shortly after the film’s debut at SXSW, as well as the film’s long gestation process and getting the most out of his cast.

How did this come about?

It’s a very long process. The script was originally written by a good friend of mine, Chris Sivertson, who tried to get it made a while back and he just ended up making other things. Ten years ago, we tried getting it made and it still didn’t happen. I was in New York at the time and eventually, I moved to LA and I remember just asking him, “Do you ever think about going back to that ‘Teenage Cocktail’ script that was so fun?” And he’s like, “Oh no, I’m doing other things now, but you should take a look at it.”

I went back to it, gave it another read and I feel like I had grown out of what it was because it was pretty bonkers in its own right – very exploitative and fun – and I think I had outgrown that. [So Chris said], “Rewrite it. See what happens and let’s see what we can do.” I started from there, then maybe a year later we pitched it to Travis Stevens. He went for it and it was another couple of years of finding the right money, which we found with backup in France. Boom, we just went right into casting. It all moved real, real quick and now we’re here.

Based on your previous work and Chris’ as well, it might come as a surprise you took the exploitation out of it.

We just grow out of those things a little bit. I would love to watch the original “Teenage Cocktail,” but with someone else making it. I don’t think I was willing to go there anymore. There were broader strokes and bigger things that I wanted to try to achieve personally for me.

I was getting a little bit of a 1950s teen rebellion movie vibe from this – were those films an influence?

No, I can’t say that was there for me, but that’s pretty interesting. For me, it had more of an ’80s sensibility going on in my head. Early on, I realized that I shouldn’t make a film about my generation, which would have been ’90s because it’s so outdated. Each year as we go on the gap gets huger and huger. When it comes to influences, all the ’80s high school films – “Fast Times,” the John Hughes stuff – was constantly in the back of my mind, but also not trying to have too much of it and keep it modern enough. You can get a sense of that with the score, which I wanted to be heavily influenced by an ’80s vibe.

Was it scary to dive into this new generation?

Yeah, originally in the script, the girls were strippers, fake ID’ing it and getting into strip clubs – that’s how they made their money. I don’t even think there was any teenage stuff going on. It was just by chance I happened to see some webcamming stuff on the news and it got me onto the internet. I was going through all that stuff, then I was just like, “Oh, it’s clear. This is what they should be doing.” It just snowballed from there. A lot of the movie just comes straight from the internet because everyone I know that has kids, the kids are really little and I thought, “How am I going to tap into teenage life?” I just went straight onto the web and that gave me plenty of material.

The central relationship in the film is so strong, was a lot of it on the page or did some of that magic happen after you figured out the cast?

It was a very healthy mix of both and I definitely have to give it up to the girls for that. Their relationship off-screen was instant and amazing once I put them together. We didn’t really have time to rehearse, but they hung out as much as they could and worked on it, so luckily for us, they knew the script like the back of their hand so that allowed us to be really loose on set and improvise where needed. A lot of the times they would come to me and be like, “This isn’t how we would say this, which makes sense because a thirtysomething male wrote it. [They would say] “We went through this. We understand this. This is how we felt and this is how we would say things,” and we used a lot of that daily. It was a really great collaboration between the three of us.

You have one of the most debaucherous party scenes imaginable in this film. Was that a crazy day of shooting?

Yeah, that was nuts. But every day was pretty crazy because it was a small movie. We were doing about eight or nine pages a day, which is horrendous and there was always something, like a missing piece of equipment or just something stupid. The stuff in the supermarket at the very end [of the film was crazy] because that was an overnight shoot and it was our last day. Everyone was super spent and just really trying to hang in there and give it our all because for the most part, it’s the girls hanging out [during the film]. It’s very relaxed and chill and we had this one big final day that everyone knew they had to [bring it]. There was a point where it’s 4 in the morning. You’re done, but we’ve got to get through it. That was the toughest day.

[For the party scene] we went pretty late and it was just crazy to control all those kids, and to keep them up and excited about everything. It was fun to shoot that. Production designer Ashley Fenton was able to go bonkers with everything [on the set] and there’s a lot of fun, stupid little things that never made it into the movie prop-wise. It was a long, long, long night, but it was a good day.

In general, was the production design fun to think about? Because you go into one of the girl’s bedrooms and it tells so much about the characters.

Yeah, I wanted the bedrooms to be characters of their own, so if you just took still photos of the bedrooms, you knew who’s was who’s and who they were instantly. These days, maybe a teenager’s Instagram is more their bio, but I feel like the teenage bedroom will always be a visual representation of who that kid is.

Since you edited the film as well, it’s interesting that you don’t waste any time in setting up the central conflict of the film in the opening scene, but let it play out as a slow burn to let us get to know the girls. Was finding that structure tricky?

We tried a bunch of different things. Eventually, that just came down to a general consensus between everyone that this is the best way to start it off, just to hit the audience early on. Then hopefully the audience gets lost into the relationship and almost forgets about that, but since it’s still lurking in the back of their head, when we do come to that in real time, the audience starts to hear the lines that you hear in the beginning starting to come back. Everyone’s almost about to expect it and then you get hit again.

Since this is a different tone for you from the other movies you’ve done, was it an interesting experience?

All the early horror stuff is a lot of fun, and I would love to go back one day to a more serious tonal horror film because I think that would be a lot of fun to do, but yeah, this is more of what I’ve always wanted to do – this kind of world and these vibes – and it just took me a while to get to it. I finally got a chance to do it.

“Teenage Cocktail” does not yet have U.S. distribution. It will play SXSW on March 18 at the Alamo Lamar C at 10 pm.