Finish of course!

No more distractions, no more interuptions, and nothing to get in between you and "filling" your girlfriend! You quickly resume your stroking, and start feeling around. Yes! You found the opening to her cervix! With your current size your cock fits perfectly into the opening like it was her vagina.

It doesn't take long for you to finish, and you sigh in pleasure as you empty every last drop into the hole. You rest against the wall and pant in exhaustion, and suddenly the wall contracts. In one swift motion it swallows you up.