suck or sucked?

i'm looking to generate some extra income, and yesterday found myself absentmindedly wondering about selling my body for sex. i've never sold myself in this way before, and maybe i've missed the boat what with the middle years of my life fast advancing, but it does seem an easy way of making money. especially as someone told me what you actually have to do. i'm talking men's toilets here. apparently the payee sucks you. i'd always assumed you had to suck them. or did i dream it? can anyone clear this up for me?