Similar to Stacey's mom. Except Sean's mom definitely does NOT have it going on. Usually referring to a friend's mom who has slept with all of his friends, teachers, coaches, and inanimate household objects.
Friends will often make fun of a "Sean's mom" in front of the son. This will be acceptable to the son because he knows his mom is a promiscuous she-demon trailer trash.
It is said that only chuck norris can count the number of men Sean's mom has been with. And hes only done it once.
Hey Sean can you bring some towels? Things got a bit messy on your mom.
Did see Sean's mom last night? Yeah I was coming out when you were heading in.
I heard Sean's mom sent out a mass text to her man friends and the network crashed.