Although the literal meaning is to fall (see picture), the verb caer and its various conjugations have an assortment of practical applications in Mexican slang.
2) Caete con la lana. This is a hold-up! Lana, like feria, billete, biyuyo or camarón is slang for money. More generally, caerse con means to give or grant. A striking way to ask for a compulsory donation is to say: caete cadáver.
3) Ya le caigo. I’m leaving.
4) Te cae? Really? // Are you serious?
5) Me cae. You bet! // I swear.
6) Me cae de madre. You fucking bet! // I swear it over my mother’s grave.
7) Se cae de buena. She’s super hot.
8) Caele a la chingada. Get lost you bastard! Caer a simply means to go somewhere. The term a la chingada refers to the most remote of places and is often replaced (in increasing tone of discontent) by al agave, a la gaver or a la verga.
9) Me cayó el veinte. I just realized something.
In cases 2, 4, 5, 6, 7 and 8, it is customary (but grammatically incorrect) to replace the letter e for i (so me cae is pronounced me cai).
Lupita: Me cai que le caíste bien a mi jefe, pero ya es tarde así que caile.
(I assure you my dad thought you were a nice guy. But it’s late now, so you should go home).
Rigoberto: Chale, te cai? (Are you serious?)
Lupita: Me cai pinche Rigo! (Fuckin’ A!)