1)Usually a female but always retarded who will pole dance for crayons, sweets or coin.
2)A very highly sexed person with downes sydrome that is struck for cash. Sex mongs are often cheeper than the regular exotic dancers just be sure to take a packet of biscuits as payment.
A person who always wants to take and not give anything while in the act of having sex. This may be someone who forces his partner for a blowjob, handjob, or positions which requires no participation from this person (Like woman-on-top) and won't do the honor to satisfy his / her partner.
This comes from the popular word couch potato, basically describing someone who is lazy, sitting on the couch and watching TV (yes, without bothering to entertain the TV set once he's done)
Kate: I left Joe 'coz he was such a sex potato, I was completely tired.
Mary: God, that must be like slavery! Glad you left him. Date an athlete this time