Charity Horns
Typically directed at middle-aged rockers wearing punk and/or heavy metal band t-shirts in public by younger fans who raise a hand with extended fore and pinky fingers, while the thumb and inner fingers are curled in. Sometime mistaken for a show of support for a Texas football team.
Dude was hobbling down the trail with a cane while wearing a Slayer T-shirt so I threw him some charity horns.