A Rutch Dudder is the opposite of a Dutch Rudder
. It is defined as a person (male or female) assists another person (male or female) putting their clintched fist into their anal passage. The person without their fist in their anal passage (Person B) holds the forearm of (Person A) and thrusts Person A's hand in and out of Person A's anal passage.
a guy puts his fist up his anus and then another guy holds his forearm and moves it in and out of the anal passage this is known as the Rutch Dudder.