Artist is Rabid from Fur Affinity (http://www.furaffinity.net/user/rabid/). Originally uploaded to FA between 22nd-24th June 2009. Commissioned by gameseeker18 and chronocelebi (also on FA)
Comic involves 2 female Slowkings (affectionately dubbed 'Slowqueens', and going by the names of Star and Luna (I'll let you guess who's who)) consuming an unknown liquid and growing large as a result... like, REALLY large - if you don't like 'em big, leave now, while you still have a chance.
Comic is related to Mountain of Flesh and Feral Flesh (also by Rabid), taking place in the same world.