Christmas joke

Christmas season is around the corner.
I've heard a Christmas joke, which made us big laugh in the class a day before.
Tony gave us a joke about Santa Clause and a boy.
A boy made a wish and wrote to Santa-Clauae.
Boy:  Santa Clause, please send me a sister.
Santa: Okay, I will. But you should send me your mother, first!
Did you make yourself laugh?
It's a kind of adult joke, isn't it?
I hope you did. I also expect you'd give me any jokes to make me laugh.
Thank you!