Ansel Elgort says he has ''amazing sex'' with girlfriend Violetta Komyshan.

The 21-year-old actor, who recently rekindled his relationship with his high school sweetheart following their split in August, admits he had ''no clue'' what he was doing when he lost his virginity when he was 14, but now feels very confident about his abilities in the bedroom.

Recalling his first time, the 'Fault in Our Stars' said: ''I had no clue what I was doing, and neither did the girl. I didn't even make the lighting good. That'd be one thing I'd do differently. It was, like, fluorescent, bright bedroom light, like, over the covers. The only thing that made me feel better was doing it again.''

But Ansel insists he's never been a playboy and prefers being ''with a girlfriend long-term.''

He told the March issue of Elle magazine: ''I prefer to be with someone I can trust. I'm more into that.

''I think I could say this: If you like someone and the sex is really good and you enjoy spending time together, why wouldn't you make that person your girlfriend? Why go around dating random girls and having terrible sex when you can be with someone you really like?''

The 'Carrie' actor also admits he loves that Violetta is a ballerina.

He said: ''I like strong women. Physical women.

''I love when a girl is like, 'I can't hang out. I have to go to class.' And I go pick her up and she's all sweaty in a leotard with her hair in a bun. That's the hottest thing ever.

''If you can find a girl who you can go to an EDM concert with, have a conversation with, who will sit on the couch and watch you play GTA [Grand Theft Auto] for three hours--and then you go to bed and have amazing sex? That should be your girlfriend.''