Since I have a body like Danny DeVito and cursed with shoulder tendonitis, the butterfly is one stroke that I can’t do. I do, however, like to do underwater dolphin kicks. I haven’t been able to make it across the entire 25 yards underwater, but I get close. I also like to do dolphins kicks starting on my stomach, rotate to my side, rotate to my back, and rotate to my other side (barrel roll down the length of the pool).
The only way that I can do dolphin kicks is using the Aqua Sphere Alpha Fin.
I sometimes get hot spots on the top of my toes from the up kick when wearing the Alpha Fins. My remedy was to apply BodyGlide on my toes before using the fins.
The only downside to using the Alpha Fin is that you can get addicted to using it. The only limitation is you can’t do the breaststroke kick with it.
Here’s a YouTube video showing the use of Aqua Sphere Alpha Fin (it was originally called Zura Alpha Fin) for butterfly and freestyle.