Effieurage is a easy and simple technique to use while grooming. Use all of your hand flat but let it mould to your horse. Can be used all over your horse in soft long strokes and this helps with relaxation, reduction of tension, reduction of pain, enhancement of venous and lymphatic return and increasing local tissue temperature, :-)
I have done a little "massage", if you could call it that, for my horse by rubbing his poll directly begind his ears on both sides. He usually gets really tight there so that helps him before a ride. I also love to stretch my horses back/butt by digging my fingernails in and scratching his croup and he will lift his back up and it really helps him stretch out!