examples of when you say rub it in?

rub it in means to make something worse
eg.
“I can’t go to the party friday, I have to work”
“Well I can go, it’s going to be heaps good!  Everyone will be there”
“Rub it in why don’t you”

OR

“Can you believe I got the same camera as you but 50% discount!”
“alright don’t rub it in”
“sorry!”

Also related is needled

eg I really needled so and so about ?????????

or so and so kept needling another party about ???????????

the context is needles cause pain and by needling someone you know ti is a sore point but you keep doing it to cause embarrassment