swinging (sex)
A niche sex act that is very reminiscent of playing on a swing (where the name comes from), or "teeter-tottering" on a seesaw, where one or two tops (usually smaller) grabs hold of their bottoming partner's body and use the weight of their hips to thrust into their anus and/or pussy. This act is also performed when face fucking by grabbing hold of the receiving partner's head instead. When two tops are involved, this sex act leans much more towards the seesaw example. Usually involves a larger female as the bottom, but it is not impossible to do it with a larger male as the bottom.
Not to be confused with swinging or the slang term for consensual cuckolding.