@gailcalled of course there are many slang or vulgar words that could be used instead of “sodomiser” : “enculer”, “mettre”, “niquer”, “baiser”...
Anyway, “somatiser” is only a medical term, rarely used, and few persons know about this word. I’ve never heard it in a slang context, nor in a transitive form. To me, “te somatiser” doesn’t make any sense.
Maybe if we knew in which context it was said… any idea, Kulfi ?