Question

What do people yell to the cumpleañero after the candles are blown out?
Responses

vete
vete

beso
beso

que lo muerda
que lo muerda

feo
feo

Answer 1

The common thing people shout is "¡Que lo muerda!" — literally "let him/her bite it!" — urging the cumpleañero to take a big bite (or have their face pushed into the cake). "Beso, beso" can be heard sometimes, but "¡Que lo muerda!" is the typical call.