Slipe'n'Slide
Getting out a Slipe'n'Slide and covering it with lube instead of water. The person at the end lays legs spread eagle with their asshole stretched wide, another person then runs and slides down the lubed up Slipe'n'Slide head first into the wide butthole.
"Awh man Susan and I did the Slipe'n'Slide last night, got in passed my shoulders!! New personal record!!"