I discovered the brand derriere equestrian and they are perfect for riding, really comfortable and invisible under my breeches :)
I feel more comfortable in classic underwear but I know doctors recommend to ride with sport ones
I was used to ride with normal ones, but recently I've heard about the bad consequences it can engender so I decided to buy sport undies. It's not really pretty but I guess it's better for us to wear them :)
I prefer normal, plain Jane undies. I've tried sports underwear before & never found anything that I liked.
I try to wear sport underwear every time I ride but I tend to forget...
I ride with classic underwear since always. But for an intensive or serious practice of horse riding (jumping, dressage, eventing, reining, vaulting...) it is recommended to wear sport underwear :)