The act of getting led on, used, or toyed with by a girl who clearly knows you are
interested in her. It is not the same as getting
friendzoned because a Tammy does not want to be your friend, she just wants to use you for money, alcohol, parties, drugs, etc.
A true Tammy will pretend to act
interested in you, flirt with you, and compliment you to draw you in close in order to gain the best rewards.
"Dude, you see
that girl I was with
the other night? She's totally hot and totally into me!"
"Bro, you're getting Tammied. She's just using you to find out about parties, get
shitfaced, and go home with other guys."