To keep a girl/guy on the side to have sexual intercourse later, because she is not eligible to play for whatever reason . Usually, because she/he is underage by a few months.
Sort of like a red shirt in sports.
Also spelled RedShirting, Red Shirtin, or RedShirtin
"Tyga is red shirting Kylie until she turns 18"- an interview with Charelamge on VLAD TV about the subject
T-Shirt as a verb. To t-shirt something is to like it so much that you would want to wear it on the front of a custom t-shirt. This can be an item, photo/image, or phrase/quote.
If a particulary large-breasted woman wears a button-up shirt too small for her bosom and still insists on buttoning all the buttons, a shirtgina occurs; it is the gap between two straining buttons over the front-most swell of the breasts. The gap is akin to the shape of a woman's vagina and if no undershirt is worn, the gap gives a peek into the world of cleavage beneath.
Person 1: Dude! Did you see that girl's boobs?
Person 2: Yeah. That button-up was too small. She totally had a shirtgina goin' on!