i've never heard anyone say that, but people do say 'to beat your dick,' also wichsen.
so, dick beaters would mean hands.

Never heard "dick beater" before but "Wichsgriffel" is slang for "fingers".

never heard anybody use an expression like "dick beaters," and it sounds like a shitty translation. perhaps "sticky fingers" or "hairy palms" would be better to imply the hands of a masturbator.

Dick beaters are hands. We used to use this word in the army. So for example if I said " Get your dick beaters off me ", it means get your hands off me.

I heard use of this term in the Army as well, but for fingers. E.g., "Get your dickbeater of my trigger" meant "remove your finger from the trigger (of your rifle)." Because of its reference to masterbation, it's use is limited.