Regardless of whether you have a penis or a vagina, everyone has a pelvic floor. It's a bowl of muscles at, well, the floor of the pelvis. There's two gaps in the pelvic floor - one where the anus comes out, and a urogenital one. If you have a vagina, the vagina and urethra both exit here.

The human pelvic floor has a couple of very important jobs. First and foremost, is keeping your internal organs inside you. The other is ensuring that peeing and pooing stays under your control.

Anyway, the most pertinent information in assessing the veracity of the twat cannon post is that pelvic floors squeeze involuntarily when you laugh.

And now let's talk about physics.

Have you ever had an experience where you try to grab a wet bar of soap with wet hands and it shoots clean out of your hand and across the shower? If you haven't, give this a go. Take the soap in your hand, and squeeze it just a little too hard. It flies right out.

Slippery, moist, smooth, rigid things will often go WHOOSH if squeezy force is applied. (sorry, we're a Vagina Museum, not a phyics museum)

@vagina_museum
As a physicist, let me just tell you that the correct thing to say is that:
Slippery, smooth, rigid *rounded* things will go WOOSH if squeezy force is applied by something *flexible*.

Other than that, spot on. You have my blessing as an ordained (although maybe defrocked) physicist.