I’m running senior tkd session next Saturday. We will do some gluteus maximus, minimus stretches which attempted to show in the video below. I forgot to say, once stretch is too comfortable, move the band above knees. We can use partners to hold legs for the resistance. There should be a good squeeze in/out. Slightly dodgy positioning but gives the basic idea. The squats one could be done in pairs with bands to try and do a basic dodge of opponent. I’ve been recommended both glute ‘cheeks’ in and out depending on types of squats. To see proper ones, I’d recommend Eric Cressey Performance videos and astanga yoga videos for the bridge positions.
For a piriformis stretch, currently attempting astanga pigeon