There are several levels of defense against this. I struggle with this constantly (my teacher's favorite pass by far) and have spent a few months working on solutions. Here's what I aim to do:
1. If they're feeding your free foot between their legs, then their far hand is dropping. If you can, grab it, and feed it between their legs to your far hand to set up an old school far-leg push sweep. I hit this all the time, works great.
2. If they successfully feed your foot between their legs, go to RDLR immediately. concentrate on pushing up and away with your RDLR hook long enough to get the other foot in their hip. It doesn't really matter if the hip foot is facing up or down, though it does change your options from the position. You really want to have their far arm at the sleeve and your inside hand grabbing their ankle, or even better threaded under their ankle (this both sets up the inversion and prevents them from grabbing the sleeve). If you can leg lasso with your outside leg, super. That's even better than hip control. You can prevent the knee slide almost indefinitely with the leg lasso, and if makes inverting easier. If you do get the hip foot in and can't get the leg lasso, either reach across to their far lapel with a thumb down grip and start trying to invert, or use your foot against their hip to create space and re-guard. Above all, don't let them get a grip with their far hand on your bottom sleeve.
3. If they manage to break down your RDLR and start the knee slide, you have a few options. You can often get to deep half by grabbing their thigh with your outside arm, grabbing under their hips with your inside arm, and extending your body to straighten their leg so you can swing under. Alternatively, you can use the underhook defense. Get an underhook with your outside arm and immediately start trying to get to your knees. Again, it's much easier if they don't have the bottom sleeve grip.
4. If they have the bottom sleeve grip and are starting to work the knee through, you're in a lot of trouble. About all you have at this point is the single leg underhook defense, where you get the underhook and as they transition past your leg you turn to your stomach with one arm around their knee sliding leg and try to transition to a single. This is very hard, especially if they have a really strong bottom sleeve grip, but it can be done and you might as well try.
This is a super powerful pass and the best thing to do is play a very active DLR to avoid having to deal with it as much as possible, but if they do start feeding your leg through you have to react immediately. You have to stay a step ahead of them as you move through these options, because if they can get that bottom sleeve grip and flatten you out you're f-ed.