up and down : moving ones mouth up and down around a hot guys large and cummy penis, or:
a male licking a female's big and yummy tits/nipples;
also makes people horny

Sucking is when you don't get a raise after 10 hard years at the same company.

Also sucking is when you like cock in your mouth wether you are male or female.

Sucking has a few definitions
1: durring sex when a man licks a girl"s boobs,2: durring sex when the man licks the pussy,3: slang for hard-core kissing.

When somone is going under losses.
sucking is term used in sex , in which a person hold his cock in his mouth and give him pleasure.