Have him invite several friends at once,
you should be naked and kneeling with a clear glass handy,
Suck them off in turn and spit the cum in the glass,
Continue until they no longer want any further head,
Pour half the glass into your hand and rub it into your hair and face then gargle the rest for 1 minute before swallowing it.
Then using your fingers scrape as much as you can off your face and suck and lick it off your fingers.
Lick the glass clean, every drop.
Ask them if there is anything else you can do for them.
Report back here in detail so everyone can enjoy your humiliation.