"Pizza" joke

There was this boy named Peter. And this girl named Tammy.
They were boyfriend and girlfriend. One day Tammy went over to
Peter's house and says to Peter,"What do you want to do?" Peter
says,"Let's have sex." Tammy answers,"Peter, I can't I having
my period now!" Finally Peter convinces Tammy to have sex with
him. They go upstairs into Peter's room, on Peter's bed and have
sex. An hour later Peter hears his mom opening the door so Peter
tells Tammy to go into the closet. Peter's mom comes into the
room and yells,"PETER, WHAT ON GOD'S GREEN EARTH HAVE YOU BEEN
DOING TO MAKE YOU'RE BED ALL RED?" Peter calmly answers,"Mmmmm!
Eating pizza!"