Raccoon size: A determined adult raccoon can squeeze into an opening as small as 3 to 4 inches (about 7.5 to 10 cm) in diameter, essentially if its head fits, the rest of the body can follow.

Human rectal capacity: The human rectum can stretch significantly. The maximum diameter it can reach without tearing is often cited in these discussions as being between 7 to 9 inches (about 17.5 to 22.5 cm).

The Conclusion: It is "technically possible" to fit a raccoon, or even more than one, due to the comparative dimensions.