Da lap or stomach of the "underneath"
partner in a
couple during
intercourse, where the "upper" person is "sitting" or "riding" on the lower one.
To avoid injury or distress to someone who's acting as a "love-seat", the "sitting" person should consider (1) how
sturdy his "seat"
partner is, and (2) how big/bulky/
heavy HE HIMSELF is, and therefore whether he might be excessively squashing his romantic partner.