suck the shit out
When one literally sucks the crap out of another individual's ass.
Person 1: my colon has been backed up for a while, I haven't had a decent movement ever since then.
Person 2: Want me to suck the shit out for ya?
Person 3: That would be lovely!
Person 2: Want me to suck the shit out for ya?
Person 3: That would be lovely!