That fat cowboy cock is going to stretch your ass.  Pushing against your hole the pressure builds and builds until your ring collapses under the force, as the head pops in, you gasp and suppress a scream.   The thickest part of the cock is up at the top just behind the head, so once the first several inches get inside, your ass clenches down and almost pulls the rest of it into your new cunt.  He lets it sit there for a minute, with his pubes smashed against your ass cheeks.  Then he starts to fuck.  He does not realize, or care, how much he is hurting you.  He uses long strokes, pulling his cock fully out of your hole on each outward stroke. He then punches in with force, stretching your ring and removing all resistance. The friction builds until you are begging him to spit on his cock to add some lubrication.  He eventually gives in and spits at the now gaping hole in front of him, but only because he wants to make it a little slicker to feel better on his meat.  After almost thirty minutes of pounding your ass, you realize that he has fully opened you up and stretched you out, since there is almost no resistance anymore when his fat cock punches into you.  He then pushes in as deep as he can, forcing you up on your tiptoes, when you feel him shoot his load inside.  His balls twitch against your ass, as they force his hot jizz up thru his cock and into your cunt.  Your hole is too stretched out and battered too close up as he removes his meat, allowing his cum to drip down your thighs.  You have just become the cowboys bitch and his cum dump.