Yeah, never ever wear underwear with bibs or shorts. What ‘extra protection’ can seams create? The time spent on a saddle on a trainer is loads more than riding outdoors, so that’s loads more time to grind those seams into your privates.
What helps me is to concentrate on not hoping around on the saddle, and checking the position of the pad several times during a ride. Standing quickly and pulling things back into position helps a heck of a lot, and post ride; getting out of those wet/damp things is important too. The sweat can cause chaffed areas to get more painful, and cause fungus and other ‘crotch rot’ to set in. Tops too can be prime growing zones for fungus. (I had weird looking rings on my chest that was caused by staying in the top for too long after a ride. That and a spray post shower knocked that out)
I rode a fizik printed saddle for months. Loved it. But over time, it started feeling worse, and I eventually abandoned it for a Specialized Avatar, that was eventually abandoned for… I think the fizik just wore down, and the Avatar had noticeable dents and movement of the scant padding on it. Recently I tried a Brooks C17, and after flirting with other brands, came back to the C17. It’s not perfect, it’s just not likely to break down as much over time as the others have. Saddles/seats are a very personal item of biking, and what fits one likely won’t fit another.
Also, on fit (I’m no expert, but have had a lot of experience with poorly fitting saddles): if your hips hurt where the leg joint is, the saddle is likely too wide. The leg/hip joint is wearing/pounding on the side of the saddle and it’s putting a lot of pressure on that joint capsule. Go smaller/narrower, or sit more forward towards the nose. If there is pain towards the centerline of the area down there, the saddle is likely too narrow, and you should get a slightly wide seat, or sit farther back towards the wider part. You should adjust the position of the saddle to make those areas feel more natural. (If male, ‘numb junk’ should not be ignored! It could become permanent!! Seriously)
No underwear EVER, and maybe try some chamois cream. (Watch for allergic reactions, as I had a reaction to a popular brand for some insane reason, and if you think a badly fitting saddle can cause pain, this was quite a bit worse!
) Oh, and saddle sores can be a thing, and are even more painful.