No vendes piñas
(You don't sell pineapples) •
It's used when you want someone to know that they're criticizing something that they're also doing. It's used to say someone it's being rude.
"Pero mira esa muchacha con ese vestido tan corto." "Pero tú no vendes piñas, mira el tuyo."
"But look at that girl with a short dress." "But you don't sell pineapples, look at yours."