Pics or gtfo.
It's from the webcomic 'Peter Is The Wolf' (the adult variant).
The quote, in specific, is "If the tits are over E'sies, it's not gay to give them squeezies"
... Frankly, even with the artist and writer both being into the small side of hyper, and breast expansion, the comic's pretty damned good, and is incredibly entertaining. You just basically get 'bonus material' on the adult side, whereas the clean version might take either a different slant on the same scene, or replace it with the comic version of 'and now for something different'.