Probably not the Chris Evans you're looking for
If you want to see Captain America naked, "Secretaries" is not the right movie for you. The "Chris Evans" in this movie is a completely different actor who's listed as "Chris Evans (IX)" on imdb. I hope that the admins can create a separate article for this actor to avoid confusion.
Sex scene, great butt shot
Robert Downey Jr. plays an obnoxious German ski instructor in this really bad romantic comedy from 1999.
80 minutes into the movie he has a sex scene with Claudia Schiffer. You have a really good view of his shapely butt, made even better by his aggressive humping movements. Fans of Iron Man will like the goatee he sports in this film, although his bleach blonde hair is pretty cringe-worthy. He's also dirty-talking with a German accent and making seal noises during sex, so I'd suggest watching this muted.
This is probably the best and most revealing sex scene he did so far.