Peeking around the corner, you see Luther's back is turned, he's totally oblivious. With a smirk, Anthro-Slob Light in your hand, you raise it up and shine it on him, eager to see the reaction it has on the young man.
Luther sighs in relief as he unzips his pants and pisses into the bowl, still unaware as his body slowly begins to change, a smile creeping on his face as the light shining on him suddenly causes his rear to begin widening, "Fuuuuck, I really had to piss." He says, sounding strangely elated as he scratches his thickening, fuzzier neck, starting to swell outward into a blobby double chin, over a much softer chest that strains his shirt.
He lets out a small belch as his hand next travel to his fattening ass to scratch it, his pants looking tighter and tighter. "Fuck, I REALLY got to piss..." His eyes flutter, his piss stream steadily increasing in volume as he shifts and readjusts his weight, his shirt unable to withstand the accumulating heft pushing it out. His pants are desperately straining to cover his tree trunk thick thighs that wobble with the slightest movement, as your friend tries to reposition his ballooning gut over the torrential jet of urine flowing from his cock, getting more erect and buried by furry flesh each passing second. Luther lets out another burp, much larger than last time, and scratches his stomach as his clothes begin to rip. "F-Fuck, I... J-Just gotta, unnf..." He grunts, gritting his mouth full of razor sharp teeth, as he pushes out a gargantuan fart that stinks up the bathroom. "Just gotta... BWOOOOOORRP--pee..."
As his fart continues, followed by more belches as you see fur cropping up along his exposed skin, his clothes becoming shredded, you see a tail suddenly erupts from the base of his spine and swish around, your friend sighing in relief as the fart dies down, "I can... ughhh..." He rubs his stomach as the flow of piss continues unabated, farting loudly again, much wetter this time, his tail beginning to flag as he puffs out his cheeks and pushes. You watch in bemusement as the seat of his tearing pants begins to expand in a different way, a large mass filling out the rump, causing it to sag. The flood of piss becomes even stronger, a pure deluge overfilling the bowl and splashing onto the ground beneath him, as he leans forward, powerful paw resting against the wall, continuing to push, "Gotta, just gotta... Mmmph!"
The lump in his pants begins to swell further, foul stench getting even worse. His tearing clothes are getting drenched in sweat, and his pants can barely stand the added weight as he massively shits himself, being torn at the seams, crap starting to ooze through holes along the waist and over the back. As Luther grits his teeth and blasts an even stronger fart, what remains of his pants is brutally torn by the largest log of crap you've ever seen being pushed out of his ass, muffles farts erupting from his hole as the massive load of shit is unloaded onto the floor of your bathroom, his stomach and ass growing even wider as he seems to accept what a slob he is.
One final fart later and Luther is panting, a big smile on his face, his pee stream dying down to a perpetual trickle, left wheezing with a considerably large mountain of shit steaming behind him. He snorts, and wobbles around, a big fat lion of a man too, "BURRRRRP--Man... I had to go more than I thought." He chuckles, "...What am I doing in the bathroom though?" He says, pawing at the loose pieces of torn clothing curiously.