our 6yr old boxer has drainage from her rectum that looks like mucous.?

An abcess of the anal glands. Have her go to the vet. They will make sure the gland is "released" and give her antibiotics to prevent infection.

My dog had this, and it was very stinky and uncomfortable for her. Dogs usually are able to "pop" their glands themselves by licking or rubbing, but occasionally they can't. For these dogs, a regular vet check is necessary or ask your vet to teach you how to release the glands.

if it has a bad smell then she probably needs her anal glands expressed. Many dogs with very short tails and very round bottoms need this done quiet often i have to have it bone with my Boston Terrier. My vet does it for free. They just stick their finger in the dogs anus and push on the glands. The mucous inside of the glands are what covers the poo and gives it all of its scent and information when the other dogs smell the poo. Just take it in for a vet visit tomorrow and ask them to express the glands, it doesnt hurt them at all

Either mucus diarrhea or an infected anal gland. She needs a trip to the vet.

It sounds like it may be her anal glands. A vet or tech can express then for you, and if you are not squeamish can teach you how to do it yourself.

If it has a fowl smell it could be her anal gland needs to be expressed.