I wear what used to be called knickers, nowadays full briefs or panties. High leg briefs don't support or feel right to me due to the narrowness of the crotch. The brands I favour are Shadowline (no longer made unfortunately) and Vanity Fair, made in the land of the free. I buy them from there, so much cheaper including postage ($6.00 or so). These makes fit my manly form better than any other I have tried and the nylon is of superior quality and is not sweaty in the summer. They are much more comfortable than underpants and are much prettier! My Lady companion calls them in her Lancashire accent,"big coomfy Knickers!" But comfort is essential, leaving you to worry about other things. There are panties made for men, such as Manties etc, These may suit you if you like bows, ribbons and things so shop around. I don't recommend support or lycra knicks, I'm trying to make my bum look bigger not smaller. I love the look of French Knickers but they do ride up, if you'll excuse the expression, into the crack of your bum!
That leads me on to shaping to look feminine. You need HIPS! Most women are larger here than up top. You would'nt dream of dressing without some sort of padding in your bra so don't think you can appear womanly without padding here too. I made my own plucked from foam plastic to be concave on the inside and shaped on the outside with a breadknife! Sounds rough but is not noticable once held in place with cut off tights over my foundation wear. You can of course buy ready made bum enhancers but I've found many to be too hard and not long enough to pad out my thighs.
For foundation wear, I seldom wear anything but Rago Shapette open bottom corselettes (again bought from America). All in ones as they are called there. Black or white or even dyed to your whim, they smooth the lumps and bumps beautifully and keep your breast prostheses in place better than a bra and of course hold your stockings perfectly. Buy by bra size, forget about the bottom bit it'll fit fine. You may need to extend the straps to fit the longer male torso. It's only on the hottest days that I am forced to abandon support and elegance in exchange for comfort and coolth to wear a bra, knicks and fake tan in lieu of stockings. Another advantage of living in a cold climate!
Stuffing my bra with rolled up socks is something I did for many years (Clean ones of course), when I thought I couldn't afford proper gel forms or chicken breast fillets as they are also know! I remember vividly trying them for the first time. It was wonderful! The weight, the feel, the way they warm to your body temperature after a few minutes so you don't notice them, all conspired to make me buy them on the spot. £190 the brace! But it really is worth it. So natural, almost real. Do try various sizes, but remember only Dolly Parton can get away with looking like Dolly Parton!
Tucking (pushing you balls up into your body, sounds painful but isn't) is something I don't often do as I don't wear tight fitting skirts, preferring clothes which skim, much more flattering and comfortable.
Having a small waist is what we all want. You can pull yourself in with a waist cincher but they are remarkable uncomfortable if you want to drive or sit. I use a tight wide belt which is tolerable even during a long day and gives me a really defined shape.
These are some of the points I have learnt over a long period of attempting to look and feel feminine. I hope you think I've succeeded. That's not me below it's of course Carole Vorderman, wish it was!