Some examples of the kind of scenes I'm talking about:
"Grounded 2: Truth or Dare" (DCX)
"Twinkology 101" (NDS)
"Major League Part 3" (Men)
"One Hour Detention" (FrenchTwinks)
I would say "The Neighborhood Kids" (GayCest) except the dad doesn't end up topping, but it's similar in spirit.

I think what interests me is the idea of an authority figure (teacher, stepdad, etc) either teaching or helping themselves to the boys who are attracted to them (such as his (step)son's friends, or a teacher instructing a sex ed class).
I know there are plenty of threesome videos that match this but I'm looking for some with more than just two bottoms.