Spanish:

--Señor, mi mamá quiere saber qué vende.

--Dile a tu mamá que ceviche.

English:

--Mister, my mom wants to know what are you selling.

--Tell to your mom that ceviche.

Ceviche is, well, ceviche. In north west of México, we often say "vichi" to say "nude". "vicharse" would be "get naked", so "Dile a tu mamá que ceviche" can be a pun for "dile a tu mamá que se viche" (Tell to your mom that get naked)