present participle. Bippy-embiggening.
Related terms: de-fatifying, re-fatifying.
Real citation: "I'm all about having a girlfriend tell me what to do, as in: Take those ass-fatifying pants off immediately and put the good ass jeans back on even if they do have yogurt spilled down the front! and Forget diapers already! Just buy the effing shoes., and of course, Go ahead and mack with the hot Brazilian guy who bought you drinks at the bar. You're not getting married for four whole days, sister! (Kidding, kidding)."
(Jessica Ashley, May 16, 2007, Strollerderby, http://babble.com/CS/blogs/strollerderby/default.aspx#20552)
Made-up citation: "I loooooooove almond butter, but I fear it's ass-fatifying me out of my pants."