A warty vagina, or a vagina with many warts.
1) you could go with classic urban dictionary explanations like:
"Dude I slept with this girl last night and she was a total toad muffin...I think I'll hit her up again"
2) or you could go for the month python approach
"I have found the holy grail of women. She was a total toad muffin"
3) use as an insult to someone who slept with your ex:
"I BET HE TURNED YOU INTO A FUCKING TOAD MUFFIN, U FACKIN SKANK"
4) use for anyone you generally can't stand
"Why do you have to act like such a toad muffin all the time?"
5) or talk about a cat:
"Carl was petrified by the toad muffin. Like literally. He's made of stone now."
6) tinder:
"met a hot chick on tinder. We tried to Netflix and chill but then I saw her toad muffin ):"