Green’s Dictionary of Slang

skommel v.

[ety. unknown]

(S.Afr.) to masturbate; thus skommeling n.

[SA]A. Dangor Z Town Trilogy 128: ‘This aap will make Reggie sat [dead] with his damn skommeling!’ she repeated in her township English. [...] Skommel is an Afrikaans slang word for masturbate.