Shampoontang 

having sex in the shower while lathering, rinsing and repeating over and over again.

I heard that there is some sweet shampoontang over in the girls locker room.

Shampoontang by Omeil and Dan April 6, 2006

Shampooning 

Verb - The dexterity required act of massaging a girl's hair while simultaneously exploring her mouth. Occurs most commonly in public spaces.

Yo look at Cliff over there Shampooning the shit out of that girl. Are we in a club or a Pantene-ProV commercial?

Shampooning by EBITDeezNutz March 22, 2011