its kinda like a pick-me-up but not rly
a pick-you-up is something that you get when your in a really bad mood that makes you feel better.
for example, some people might get a new pair of shoes after breaking up with their boyfriend to make themselvels feel better. that is called a pick-you-up.
"thanks for the snickers bar. i really needed a pick-you-up."
"lets go shopping, i need a pick-you-up"
"sex was great! thanks for the pick-you-up"