From jock to a fat dudes (inanimate TF)

The user is an athletic or thin guy, and after coming in contact with a special brand of "Fatboy" underwear he gets transformed into a cock that's attached to an obese 20 something year old man. After putting on the underwear the user will feel as their body begins to shrink... Getting smaller and smaller until they are around 5 inches tall, then it happens they feel as their legs begin to spread apart growing big and bulbous with some light wrinkles and sacking down into two testicles. Their arms fuse into their torso becoming the base of the penis as their head becomes a smooth cut mushroom capped tip, over this period the user feels a form of comfort washing over their mind mixed with erotic pleasure, their eyes and nose vanish as their mouth becomes a small little hole on the tip that leaks out sweet seamen... The user feels as if they are attached to something a heavy flabby gaint of some sorts, their body feels blanketed in thick plush walls as only their little head/tip can stick out of it seeing the light turns out a new human has formed to replace them, a big fat male human and the user is now his cock. The user can make the fat guy look and act however they want but they should stay as the pov of the penis rather than the human they're attached to. The underwear that causes the transformation is a part of the made up "Fatboy" brand user can pick any type of undergarment of any color to put on to cause the transformation and the fabric shall always be described as super soft and the most comfortable thing the user has ever put on. The fat guy the user becomes attached to should always be obese with his flabby weight suffocating the user in softness. Users tip for a month should spew out spurts of sweet white liquid, the fat guy should be prone to touching his cock aka touching the user. Whenever the fat guy puts on underwear or pants the user should feel the sensation of getting crushed and the built up pressure might turn the user hard causing them to feel the most euphoric feeling ever as they become a boner.