This refers to the early years of Tony Danza. Before Who's the Boss, Danza's porn name was Tony Nadz. His signature more was the danza slap where he smacked the girl across the face after receiving oral sex and would call out "Danza". He was known to leave welts.
After that hummer, I slapped her across the face with my wang and hollered "Danza!" She was impressed.
Similar to dry humping, wet humping occurs when two partners engage in grinding without insertion in the shower, hence WET humping. The penis may turn red the next day if wet humping persists for more than 15 minutes.
My dick hurts from all of that wet humping last night.