Try using a bit less bridle it helped me a lot
I love D-rings they aren’t a very strong bit, my horse loves her D-ring snaffle the cool thing about it is it bends outward to fit in the mouth better
On my pony used to do the exact same thing wasent strong but it gave the illusion he was strong because he was on the forehand so I put him in a wilkie (beval) and now he doesn’t lean at all you could try getting a double jointed wilkie if yours prefers that I like the wilkie because it give a tiny bit of leverage but not as much as a Pelham or gag I wouldn’t say D ring as that is simelar to a full cheek which is for horses that tans to be nappy or arnt very straight also a Waterford tends to also be for nappy and also strong steering horses.
Hope this helps
One of my young horses used to lean on a double broken snaffle in the ring and recently I swapped him to a straight short shanked Pelham. This is for jumping but in general he likes this one a lot cause he can maintain a constant contact in it but not lean on it too much. It’s not too strong either which is really nice
Does your pony pull on the reins often? My favorite bit is a French link.
My pony is quite hard mouthed and bites down on the bit but still sensitive (teeth get checked regularly) and i’ve had her in a double broken eggbutt snaffle for quite some time but then she started biting down on it. I switched to a D-ring single jointed copper roller which works fine but I don’t like the nut cracker effect and she seems to not either. Any recommendations? I’ve been thinking about trying a straight plastic/rubber