American Sign Language:  "ketchup" or "catsup"

---

KETCHUP =  "Cat up."
I'm not kidding.  This is a real sign and it is very popular.  This sign is used by most of my friends who attended "Deaf Schools."
It combines "CAT and the fingerspelled word UP."  Ha! I love this sign.  But, if your local teacher or friends don't like it, you can always scroll down and use the generic version (scroll down) of "pounding on the bottom of the bottle."

Note: (variation)
You might see people doing the sign "CAT" with an "8" handshape instead of the "9" hanshape that I use. That is fine. They are both good.  Some people even do "CAT" with a "G" hand that closes. (Which I don't recommend, but it is still a legit version of "CAT.")

---

KETCHUP:
CAT-UP variation 2:
You might also see the "up" concept signed by poiting upward or by moving an "A" handshape upward (the thumb pointing up).

---

KETCHUP:
Here is a general version that looks like trying to get ketchup out of a bottle by smacking the upturned bottle twice: