All through the series, Yamcha seemed to me as the typical over-compensating closet case. Maybe all he really wanted was someone to give him that push into the forbidden pleasures of the same gender, or maybe just wishful thinking, whatever...
So basically, Yamcha has a self lubricating man pussy or grabbed a random tube of lube (like it usually happens) and offers himself to Son Goku... or something like that *lol
Man, cel-shading is hard. I really admire those guys that know how to use it. It may seem like a lot less work, but it actually forces you to edit yourself and make the most out of 3 layers or color