"smokin' the bone"..."giving head"..."cocksucking"..."doin' the nasty"..."oral sex"...the act of performing fellatio on a penis until said penis ejaculates.
Generally a pleasurable experience for the person being blown...depending on the person doing the blowing, not so much.
My old girlfriend Valerie had a tiny mouth, but enjoyed giving me a blowjob on Friday nights, when I came home from college.
I would show my appreciation by saving up 3 days worth of jizz, and dumping it down her throat while I forced her head down deeper, causing her to gag and spit.
She seemed to enjoy this and even suggested we shoot some video of the event...