We have someone who comes by to massage horses you just have to make an appointment and she is amazing and the horses love it! She uses different ways I’m not sure what they are all called but my horse is relaxed and happy to work within the next day!
I groom my pony before and after every ride, (rubber curry x2, hard dandy, soft dandy), but i've never paid someone to massage him. I also do carrot stretches and stretch the limbs by hand. Evention Tv on youtube has a good stretching video which is basically what I do with my pony.
I Stretch my horses legs before every ride. With the front legs you ask your horse to lift it up and then you bring it forward and up a bit. With the back legs I just lift them up and put them back down.
I stretch and massage my horse all of the time!!!!! I just started a couple of months ago, but I like to do it before I ride in he wintertime to get her muscles working and moving, I also will do it in the summer, I think anytime is fine! Also I just stretch her legs and neck and head and push on certain points on her body. Hope this helped!