[Fesshole voice] Whenever I visit someone's house, I make a point of going to the loo right after they do to exert my dominance.
@infernusgoatus Also, stuff the hand towel in the sink and leave it running right in front of them. Its not like it was going to overflow anyway, they were right there!
If you suspect they will not invite you back, get even preemptively with an upper-decker.