With her mouth.

You can’t help but be surprised. With the ease of a pornstar, your mother sinks herself onto half of your new appendage, not gagging in the slightest. The tightness of her lips. The bobbing of her head combined with the ministrations of her tongue. Even the swallowing motion feels like something out of a hentai fantasy. Your hands end up taking hold of her shortened lochs, tugging her lower onto you. Her disposition doesn’t so much as waver.

If anything she seems happy that you’re forcing her deeper. The wet warmth of your mother’s mouth summons a spurt of pre-cum down her gullet. She swallows the spill greedily, silently beckoning for you to give her more. At this point you have to, right?

That familiar tingle swelters behind your newly expanding package, and the urge to cum pounds into your head like a hammer to a nail. You have to release.

“M-mom. Mom I’m gonna cum. Can I cum in your throat?”

She nods lightly, giving your shaft a slower bob before sinking to the base and humming. Your bulge stretches out her esophagus, the head of your cock ready to burst. Then it does.

At least a cup of seed floods through your cock and into her belly. In seven spurts, each not dissimilar to the spray of a tightly squeezed turkey baster, your semen travel into her waiting stomach, providing an apparent portion of her breakfast. Satisfied, but curious, you pull her away, allowing her to take a breather. She hardly even coughs, rather clearing her throat and sitting back in her place at the table.

“Happy, sweetie”, she asks, a slimy grin on her lips.

“Almost. Would you rather my balls swell twice as large after every load until I cum in either someone’s pussy or ass and then return to normal, or my balls grow to the size of your breasts permanently?”

“We both know that you wouldn’t want to have to always lug around a pair of gonads that heavy. How the first option. At least then you would only have massive meatballs some of the time.”

You half laugh and half cringe at her comment, but upon the completion of your mother’s response, you feel your balls fill back up with seed, sinking lower. They don’t stop just yet though, as how you’d described, each orb has doubled in size. Your cock bounds back up to your stomach, now harder than ever despite having just erupted.

“I have a few more questions, mom.”