Green’s Dictionary of Slang

(US) to handle or feel an object or person.

1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant II 76/2: Mummock, mummick (American), to handle any object. To handle or feel the person.
1903		Nat. Trib. (DC) 7 May 4/5: The Lord made potatoes to grow in the ground [...] and to be boiled, baked or fried, but never to be mummicked over that way.