As the penis is commonly an ejectory organ I would suggest that putting anything in the entrance would be sore, if you get my drift.
However, It was discovered on a space mission that a frog can throw up. The frog throws up it's stomach first, so the stomach isdangling out of it's mouth. Then the frog uses it's forearms to dig out all of the stomach's
contents and then swallows the stomach back down again.
R V Brown & Others many years ago involved a group of SM oddballs nailing their penises to boards and the like, that may have been what you were thinking of?
My Law lecturer had a bit of a thing for that particular case; then again we're pretty certain he blew his load in his pants one day when he got over excited when answering a question from the class babe.
If you enjoy dining out or the odd takeaway or even have a yen for school diners,then read this link and avoid the places mentioned (interactive map included).Now I know that this subject seems to be a tad off thread but,,Why would a girls junior school be changing nappies near the school canteen?.