hacerse en los pantalones

1.
SpainLatin AmericaGeneral Spanishvulgarinformal
- To urinate or soil one's pants (literally), typically as a result of extreme fear or anxiety.
- To lose control of one's bowels or bladder because of terror or intense stress.
2.
SpainLatin Americacolloquialinformal
- To be extremely frightened; to be terrified (used figuratively and often hyperbolically).

Examples:

ES: ¡Se veía como que estaba a punto de hacerse en los pantalones!
EN: He looked like he was about to shit peach pits. And it's not "nothing" now.
ES: No tanto como hacerse en los pantalones en P.F. Chang's, pero aun así.
EN: Not quite "soiling yourself at P.F. Chang's" embarrassing, but still.
ES: Sangre nueva a punto de hacerse en los pantalones.
EN: I seen that look. New blood about to pop his first cap.
ES: - Tenemos disfraces que hará a tus vecinos liberales hacerse en los pantalones, como la página de inicio "BreitBart".
EN: - We also have costumes that will make your liberal neighbors Demo‐crap their pants like the "BreitBart" Homepage.