An old american 1980’s sex comedy, kinda like ScrewBalls.

One scene there were two kids had sneaked into the vents of a house where there was a party going on. Then they were looking up through the vents at the under-breasts of the women partying above them.

Another scene there was an old man, probably the principal of the school sitting in a car.  Then this girls passes a hose into the back window and knocks him out with the car fumes.  Then she presses her breasts against the glass next to his face to prove that he’s knocked out.