How strange! Never heard of anyone being able to "feel" the hemipenes... In my experience, you should always probe. I've had too many friends who think they are buying females (particularly on craigslist) and then bring them to me to sex, and we find out it's a male... I've told them to buy probing kits, and I'd show them how, but it still happens. Just recently picked up a number of girls from another local breeder and I probed every one. Two were boys, and so I didn't get those two. It's a good practice to probe every time... Once you get experience with it, its really not hard. I can do most girls by myself but the squirrelly ones, my husband will hold steady for me.