Monkey headache 

Brain freeze. When you eat or drink something cold too fast.

Shit, dawg. Downing that icee just gave me the worst monkey headache.

Monkey headache by Yoyomom April 19, 2020

Headache Money 

Money paid to the nanny for sexual favours when the wife complains of a headache.

Employer: "and that will be your weekly salary."
Nanny: "Does that include headache money?"

Headache Money by Eric_to_the_F March 26, 2008