Like hydro said, its called prolapse.

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Treatments

Prolapse can be treated at home or by a vet. Before you do anything, bring your frog to the vet first to check it out. That's always the safest route. If a vet is not accessible, there is a way you can push the intestines or gonads back in. Be sure to keep the protruding tissue moist; some people recommend using a sugar water solution to shrink the tissue. Using a wet Q-tip, gently coax/push the hanging tissue back in the rectum without twisting the tissue. This method may work in minor cases, but may reoccur. So again, it is best to see a vet on this one. If it is the gonads that are protruding, this method may not even work at all and a vet is a must see.

Prevention

Prolapsed intestines/gonads can occur for no reason at all. Or it can occur because of large meals or food/substrate that gets digested improperly. My advice to you is to feed your frog in small quantities and do not feed it anything it cannot swallow.
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