Its a German insult this word literally translates to “pleasure newt,” which is what you’d call someone who is sex-crazed.
man 1: look at that guy he looks like a LUSTMOLCH.
man 2: is LUSTMOLCH a new German lube or something?
man 1: no he just looks horny as fuck
man 2: oh... same
man 1: *smirk's*