The sound of balls colliding with the chin during fellatio.
Matt had difficulty expressing a logically coherent idea while the president's balls where Schlapping him.
The sound made when two fat Republicans are having sex.
Mercedes and Matt could be heard schlapping four doors down the hall.
A Combination of Slaps and Schlong
When your dick physically slaps something
Or Alternatively when the Sex Is Good
"Yeah I just Schlapped my meat on the counter for literally no reason" or "Yeah ig that dick really Schlapps and after I start playing Clash Royale"