Since Cowmeat is neglecting his own thread (Shame on you! >:C) I'll butt in here!
When getting rushkicked while defending there are mainly 4 outcomes.
1. You execute a perfect knee grab, DM'ing the knee. Now it's just up to you if you want to punish him with a kick or a punch. Don't let go unless you're a dumpster baby, be sportsmanlike!
2. He kicks you, you get DM'd. You're likely to lose but use other arm to grab him and try to retaliate.
3. His kick doesn't DM, and is stuck in you (Not "stuck-stuck", but he is keeping it there on purpose). Don't do erratic movements that will result you hammering your own joints on his foot, instead try to grab his thigh/knee and work around it.
4. You both miss each other, you still have feet on ground since you didn't try and kick, so you're better off for round 2
This is a really good guide but I feel less and less people are active in taekkyon so I feel like I can't practice online.
Any tips ?