For some reason, I imagine a lot of people at CHB getting tattoos. Some would be romantic, some would be in-the-moment, and some would be just because. He are characters and their tattoos.
Percy-Owl holding a trident (PERCABTEH!) on his Achilles heel. And another trident (Cabin 3!)
Annabeth-Same as Percy (to match)but another owl, not a trident
Frank-Skull and crossbones, but crossbones are arrows on his bicep
Hazel-I actually can't imagine 13 year old Hazel with a tattoo
Jason-Rose entwined with lightning on his stomach
Piper-Lightning and rose tramp stamp
Leo-Portrait of Calypso on his back
Calypso-Hammer on her tricep
Connor-Spray can tramp stamp(drunk)
Travis-Spray can tramp stamp with Katie's name(drunk)
Katie-Saw Travis's and immediately got a white lily and red rose tramp stamp with Travis's name(drunk)
Clarisse-Classic Navy and Army tattoos, plus a key over her heart
Chris-Lock over his heart
Thalia-I figure the Hunters have a special tattoo
Nico-Skull on the back of his neck
Rachel-Paintbrush and Palette on her ankle, Bay leaves on her wrist (look up Pythia and bay leaves)
Don't judge. For some reason I like tramp stamps.