DnD Sex Edition

Purple worms are gargantuan cave-dwelling creatures that produce eggs through hermaphroditic reproduction (source 1).  While worms lie next to one another to have an exchange of sperm (source 2) and then lay eggs, the purple worm does not have the Intelligence score needed to give consent to mating with a PC. That doesn’t mean the PC can’t try!

You feel the rock beneath your feet rumbling as the purple worm, impossibly large, moves slowly, but inexorably towards you. You’ve been thinking of this moment since you first entered the cave. Possibly since you first heard of purple cave worms. What a conquest! Worms mate lying side-by-side so you disrobe and lay down on the ground. The creature will align itself next to you so you can offer sperm and drink down its offering. You’re pretty sure the distance between your cock and mouth will make up for the size difference between you and the worm. I mean, theoretically, the worm genitalia will be larger but close together, right?

The worm continues its slow, inevitable approach. Until it is 10 feet away. 5 feet. Its maw yawns hugely, gathering up the earthen ground and you along with it. 

PC takes 6d6 acid damage (5e) or 4d8+12 bludgeoning damage (Pathfinder) as they are swallowed whole. Initiate combat with the PC swallowed.

If the PC has enlarged to a huge or gargantuan size: The worm’s body presses you firmly against the cavern wall as it moves past, ignoring your attempts to recreate worm reproduction. Disappointed that your plot failed and you’ll need to find another purple worm to try and seduce, you fail to notice the worms tail until it is too late.

PC takes 3d6 + 9 piercing damage (5e). Make a DC 19 Constitution saving throw to determine if the PC takes 12d6 poison damage (5e).

Alternatively, make a DC 25 Fortitude save to determine if the PC takes 1d4 Strength damage (Pathfinder).