The Creepy Tongue Pumpkin

The Creepy Tongue Pumpkin
Don't you hate it when your coworker puts their tongue on the back of your hair and says, "I love the taste of your shampoo?" I don't like it either. My coworkers do this to me all the time. It used to not bother me, but lately, as my hair has been thinning, I can feel the texture of their tongue on my scalp and it is a bit creepy. I tried to look up whether this was inappropriate in the employee manual, but it wasn't listed. What do you guys think? Should I complain to OSHA?