When one exercises (often using bodybuilding parameters) to such an extent that his or her body becomes literally "swollen" with muscle. Simply put, it's when one becomes buff.
Lantry: i been hittn da gym an I be gettin' lumpy as hell
Scott: So fascinating! Well buddy, I think you have certainly increased your muscle mass as of late. Would ya be a pal and teach me how to also become more muscular?
Lantry: heeeeeh(ll) yeah, my white nigga. We gonna' get swole! Go ahead an grab Ebenezer! See if he wanna go!
Scott: Golly, ya mean i can bring my compadre? Gee willikers, I'm roused!
Lantry (partially to himself): haha, dad nigga said "gee willikers!". Hahaha