Snooki to JWoww -- CONGRATS ON PREGNANCY ... You're Going to Crap on Your Doctor

Jwoww isn't just gonna squeeze out a kid in July, she's also gonna push out a big ol' steaming dump ... so says her "Jersey Shore" BFF Snooki.

Jwoww made the baby announcement on Christmas Day ... and hours later, Snooki (who already has a kid) posted a screen grab of a recent text convo they had, in which Snooks eloquently describes the miracle of child birth.

As for JWoww -- real name Jenny Farley -- she posted a picture of her growing fetus on Instagram ... along with a note from herself and fiance/baby daddy Roger.