machacársela

1.
SpainLatin Americavulgarcolloquialinformal
- To masturbate (oneself), typically referring to male masturbation.
2.
SpainLatin Americacolloquialinformalpejorative
- To beat, thrash, or physically strike someone.
- To defeat decisively or overwhelm an opponent.
3.
SpainLatin Americacolloquialpejorative
- To exploit, fleece, or corruptly take advantage of a person or institution for personal gain.

Examples:

ES: Mis amigos músicos entraban al baño cada cinco minútos a machacársela.
EN: And my musician friends kept going in to jerk off.
ES: Que no, enano, machacársela está de puta madre, a cualquier edad.
EN: Jerking off like crazy is great at any age.
ES: Mi puto error, por pensar que tú podrías ser ese que romperías la honorable tradición que hay por aquí, de machacársela a la oficina del Alcalde para llenarte el puto bolsillo,
EN: My fucking bad, for thinking that you might be the one. To break an honored tradition around here. Of jerking off the mayor's office from its back fucking pocket,
ES: "¿Vas a machacársela al atontado de Matt en la cabeza?",
EN: "Are you or are you not gonna yam it on Matt's stupid head?"