To prod your penis into the anus without inserting it for pleasure. Usually only done by homosexual males but occasionally straight men do it as a tease to other men in public places such as change rooms and public showers.
"man i can't believe what i just saw. while kenedy was changing colin walked up and plomped him."
by Tekasumbowdee October 04, 2009
a very small man in a very big hat
.... plomp says it all dont you think ....
by Aaron Waddell June 21, 2008
To rip your balls off and smack someone in the face with them.
Kassie, i am going to plomp you!
by FattyFuk October 18, 2011