Your eyes are fixated on the masturbating kangaroo.
You are so aroused by the sight.
You notice the creature’s big ass; its butt is lifted off the ground. The large thick tail lifts sways form side to side as it masturbates.
The pole is covered in a wet liquid as it slowly emerges out of the pussy.
And your eyes meet the butt-hole. It’s huge! (and the ass itself)
The masturbating kangaroo arouses you so much.

You keep gazing at the beast’s butt hole and suddenly you develop an urge to fist that nice ass.
You slowly inch forward. Not knowing what the kangaroo’ reaction will be, you quietly sneak into the cage; towards the ‘sexy’ masturbating kangaroo; you look around double-checking that no one sees you.

The juddering ass is inches away from you; you rub your sweaty hands together. With a smirk on your face you reach for the large tail and grab it, holding it firmly. Your other hand starts to rub the butt-hole;

Then abruptly you plunge your hand into the ass.
The inside is warm and there is an arousing smell coming from the beasts back-end.
Your hand slides in without effort, and you keep going until your elbow. The kangaroo’s ass is jerking back and forth quicker…
You start to fist! Moving your hand in and out of the kangaroo’s ass. Faster and faster you fist.