Yellow

During holidays, soccer referees send their families yellow cards.
Why is sperm white and piss yellow? So you know if you're cumming or going
Roses are red, bananas are yellow, wanna go out with a nice little fellow?
The last thing I can remember was the yellow ball speeding toward me. I swung the racquet, and then things got fuzzy.
What is yellow and goes bzzzzzz? An electric banana.
What's yellow and always points to the north? A magnetic banana.
What's yellow and writes? A ball-point banana.
What is yellow on the inside and green on the outside? A banana dressed up as a cucumber !
What's black, white, purple, yellow and blue? Sugilite, opal, and sardonyx fighting over a gumball.