That thing your mom does when she's driving, you're in the passenger seat, and she comes to a hard stop, so she puts her hand out to stop you from moving forward.
Can also be done outside of a car, if one intends to stop another person from moving forward for whatever reason.
To repeatedly answer something like "your mom" to any question until the person you are answering to is on the floor, screaming out the name of a third-rate comedian repeatedly.
Bill: What are you doing?
John: Your mom.
Bill: No seriously?
John: Your mom.
Bill: It's not funny!
John: Your mom is not funny.
Bill: Stop it!
John: That's what your mom said.
Bill: BOB SAGET! BOB SAGET! BOB SAGET! BOBSAGET! BOB SAGET! BOB SAGET! BOB SAGET! BOB SAGET!
(Tim walks in)
Tim: What happened?
Bill: Your mom.
Tim: ROB SCHNEIDER! ROB SCHNEIDER! ROB SCHNEIDER! ROB SCHNEIDER! ROB SCHNEIDER!
PWND!
Bill: I love your momming
To repeatedly answer something like "your mom" to any question until the person you are answering to is on the floor, screaming out the name of a third-rate comedian sporadically.
3. Or treating someone like they are your child. (Mothering them)
Oh my god Becky! Did you see that little baby girl with the "I <3 Equal Pay" onesie, sitting next to her brother in the Frida Kahlo onesie? I don't know where their mom shops, but that is "Momming" with style!