Pee, of course

John watched his Mom's throat flex as she swallowed a lot of the spit she was making. Sure, she'd been his urinal all day, but she hadn't actually drank any of it. John felt pretty certain he could manage a little pee through his hard-on... maybe a pissing blowjob would be fun.

It took some doing, but pretty soon he was sure he was dribbling a little piss into his Mom's sucking mouth. He watched her throat flex imagining her swallowing his waste... but if was only a few tens of seconds before she realized and dropped his cock.

"Are you pissing while I blow you? You fucker!"

"Shit, sorry Mom, I didn't get to finish peeing before. I thought I could hold it back"

Heather wasn't really that mad at this point... she'd been tasting his piss anyway. But first the failure to go deep enough... and now this...

...

Again, a flash of inspiration.

"John, do you think you could pee really hard? Like really **** it out?"

"Umm, yeah, sure"

"While you are hard and in my mouth?"

What freaky shit is Mom getting in into, John wondered.

"I dunno... I can try"

"Ok baby, here is the deal. I've been trying to gag myself on your penis so I would puke and could fill the bile tube, but I can't quite hit it. When I ... take you deep I want you to piss as hard as you can. Just a brief spurt and save the rest to do again. Maybe that will do it"

John was impressed. He figured that a good deepthroat would be how they filled the bile tube, but didn't realize she was doing it intentionally. And the idea of pissing to make his Mom puke... almost made him too hard to do it!

"Ok mom, let's try"

She returned to her hard and fast blowjob, and John relaxed to let his dick trickle a little piss in her mouth... leaving the channel open, as it were. He watched her tense up, open wider, and then drive her skull into his groin. He pushed with all his strength, on quick shot burst, and watched piss explode out the sides of her mouth... but not even a slight gag.