A cowboy shower is a portable shower that you can take on the road with you. Typically, it is a shower you set up in your horse trailer. Here are three Amazon products for your DIY shower.
A basic water pump / shower head combo works great as an emergency backup system.
If cold showers really aren’t your thing. Solar shower works great during summer. You simply fill the bladder with water and leave it hanging in the sun.
You would prefer a heated shower. You have access to either propane tank or electricity on the road and probably have some kind of water storage capability in your trailer.
Having a cowboy shower on hand can be a great thing to have if your horse winds up getting injured. If your horse gets a cut or gash on the trail, being able to rinse it out properly and doctor it back at the camp site is going to be a great help.