a Smithy
A Smithy is when you stick a finger up a girl’s butt. It’s for fun, or because you’re angry, or just bored. The goal is to get to a full Smithy with your whole fist.
My brother did a Smithy to his girlfriend and got caught by her dad.
I did a Smithy to my crush and now she’s my girlfriend.
That guy at the party did a full Smithy and got kicked out.