This is a nod to their earlier camping trip which was the core of the original "Tales of the New Teen Titans" miniseries (which gave origins for Cyborg, Changeling, Raven and Starfire)
Sigh, this was the (happy) era when it was the Titans that defined Dick's decision to stop being Robin and become Nightwing, and had bugger all to do with Batman in a snit, I still miss it.
Oh, and work that 80's sleeveless T Dickie boy! (Not sure about with those trousers and shoes, but never mind.... and "Yes" I know the outfit Kory is wearing is more blatant, but we focus on our fancies!)
And Perez always drew Gar being such a hairy little dude, especially considering he's about 4 years younger than smooth-as-silk "Legs" Grayson.