Green’s Dictionary of Slang

scum v.

(US) to ejaculate.

1998

‘Bazarov’ A Rube’s Story 🌐 I thought ’bout Arnold an’ Dolores an’ al-most scummed m’ pants right there in the store.

In phrases

scum (someone) out (v.)

to disgust.

1998

A. Warner Sopranos 101: Ah dinnie scum us OUT!