Dogs love rolling in fox poo and hence need a bath. All fine. Have a waterproof Tuffie ready for the drying time.
Why do Dogs Roll in Fox Poo?
It is not known for sure, but many predators roll in smelly stuff and it might be a way to disguise their own smell. You see wild cats roll in soil and leaf litter too. Apart from that guess, it is hard to know exactly. It must be said that smelling strongly of fox or badger doesn't seem to be a good idea if you are trying to sneak in on a prey. Stags wallow in peat bogs till they are black all over. It has been suggested that they do this to look bigger and more dangerous in darker shades. So far nobody has given a proven explanation, but every dog owner can agree that it is an inconvenient habit.
Teach "Leave it".
It is probably unrealistic to teach a dog not to be attracted to rolling in fox poo, but if you are walking your dog and see him sniffing and getting ready to rolling, you can at least teach him the "Leave it" command. This can soon become a manifested notion so that he won't attempt to roll if you are there. He will probably enjoy a good, smelly roll if you are nowhere to be seen.
Cleaning.
Amazingly poo will come off quite easily and sometimes a hose down is enough. An outside hose is usually enough. I tend to take my dog in to the downstairs shower, which has become the dog shower. Normally I rinse off mud, but occasionally it is fox poo. If you feel you need something a bit more drastic, a VERY mild baby shampoo or, better, a dog shampoo is good. Make sure all the shampoo has been rinsed off his fur as dogs can be sensitive to soaps. Use a towel to get the excess water off him.
In the picture below I must have said "Ohhh Roi!!!" because he looks like he knows how unpopular he is now..... I never scold my dogs for this, but they know they are heading for the dreaded shower.

After the bath.
Now you have a nicely smelling dog, but he is damp. After a lovely walk, he will want to lie down and this is MUCH better done in a WATERPROOF dog bed. You can take off most of the moisture by leaving a towel in his bed, but it really is preferable if you have a waterproof base bed. The Tuffies Dog Beds are all 100% waterproof and no damp will get in to the stuffing of the beds. This is very important because a slightly damp bed will be less insulating and a damp smell will tend to develop. In a waterproof Tuffie, you avoid all those problems. In a Tuffie bed your dog will dry up completely and be nice and fluffy shortly.