Chup is the watery substance in the ketchup bottle usually it comes from not shaking the ketchup bottle enough or at all the word originated from the 4 last letters of ketchup
Ryan:hey dude can I have some ketchup
Aiden:yeah sure man itâs should already be shaken
Aiden: *hands Ryan ketchup*
Ryan: *pours ketchup but only chup came out
Aiden: Jesus,bruh thatâs a lot of chup
Ryan: yeah