This is easier than snow types as you just need to think of every synonym for a penis and every one for hitting. Saw it on porn and I thought it was hot, blah blah conditioning blah blah. There's some really good erotic massage videos to give you some hints if a game plan isn't set. They would give many nightly but polite thwacks here and a thuds there A lot of people are into that kinda stuff.
Was around the time the Melborne shuffle became popular.
Does anyone know why he does this? I think part of it is that it makes the cock feel like it's something big and hefty, which can make the guy feel great about himself. Degradation is a pretty common theme in porn, either in overt or covert ways. A lone trumpet snaps the frosty air as they kneel in unison, lowering you into your final resting place. I'm pretty sure the lady is in charge when your dick is in her mouth and she has the option to bite down. Joking aside, it's likely an artifact from his watching porn and wanting to try it out on you. On a serious note, dick slapping is just fun.