Try this relaxing but highly effective glute stretch
Most times when people stretch their glutes they lie on their back, cross one ankle in front of the other thigh and pull with both hands on the back leg.
This is OK but the problem is that firstly your shoulders and upper body are tense during the stretch
This is tension you just don't need when you are trying to relax into a stretch!
And secondly your lower back tends to round and this means the stretch is less efffective.
This simple variation of the stretching technique is much more effective and much more relaxing for your upper body.
Start by lying on your back with one foot on a wall.
Have your knee at a right angle so your thigh is paralell to the wall.
Now cross your other leg in front of your thigh.
To increase the stretch all you need to do is tilt your plevis and dig your tail bone into the floor.
Keep your upper body (especially your shoulders) relaxed.
Breathe and relax into the stretch and hold it for 30 seconds.
As your get more flexible, move your butt closer to the wall.
We think this is a fabulous stretching technique.
It's worth doing regularly to keep your posture right which protects your lower back from strain.
Also you need flexible glute muscles in taekwondo if you want to kick high!