Animaniacs - https://youtu.be/lY2kC5fZG64

"I found Prince!"

-"No no, FINGERprints!"

"I don't think so..."

Not a line, but in Ratatouille there's a point where Linguini is trying to explain to his love interest that he's being guided by a rat in his hat and he's saying, 'I've got a tiny... little...' We see the reaction shot of her looking confused/disgusted and very quickly glancing down at his crotch.

It's just a fraction of a second, but a great gag for the grownups anyway!

I’ve been forced to watch Frozen about a million times over the last few months. So the one that sticks out in my mind is when Kristoff asks Anna if she knows Hans’ foot size, and she just says “foot size doesn’t matter.”

Cat in the Hat, when the Cat trips over a garden implement and says, “Dirty Hoe!”

The bit in shrek where shrek says farquad is compensating for something with his massive castle

Zootopia: "I may be just a dumb bunny, but we are good at multiplying." Judy after calculating Nick's taxes.

SpongeBob had a lot of them. There's one where SpongeBob tells Patrick that his genius is showing and Patrick covers his crotch.

Wish I could find a clip to post, but there's a Garfield special ("Babes and Bullets") themed as a black and white detective movie, and the line "Being a private dick isn't easy with a name like Sam Spayed" is forever burned into my memory.

Not my 'favorite' as I think Ron Howard is a hack and strongly disliked his retcon moralizing of Seuss's story, but it's pretty wild that the live action The Grinch has a reference to a key party (i.e. swapping sex partners based on what key you get) as the baby Grinch arrives down from the sky.

https://youtu.be/N7VUU_VPI1E

[off topic?]

Back in the day, cartoons were played before the main feature. They were made for adults to enjoy and kids to follow if hey could.