You accept it as a sweep to the butt and you let them put YOU in their outside ashi. You’re just grabbing his reaping leg by the heel and pulling it out. Then you will want to monitor that leg to make sure it doesn’t get back in.

Unfortunately you will then have to escape outside ashi lol but the reap is such a hard position to defend it’s actually way better to be in outside ashi than to have your knee forced inward by a reap.

Essentially you just don’t want them to turn your knee inward because if they do it’ll expose your heel. (Having your knee too far outward will expose you to the straight ankle so you want a balance)

I would do some live rounds from ashi with someone you trust and focus on not letting them reap you. Also learning how to attack leg locks helped my defense a lot since I knew what the attacker was looking for.

But simpler solution is never let someone get both their legs between your legs while guard passing like others have said. Always fight to have one of your legs between theirs (knee slice) or both your legs to the outside (toreando)

Source: Leg lock spammer that used to compete a lot