Zak: That’s a common issue with packers, honestly. Many of them are significantly larger than the average flaccid penis, for starters, but part of the problem is how many people wear their packers. Often it takes some work and shifting around to figure out how to best wear your packer (should you point it up, lay it along your leg, wear it higher, wear it lower, or what? that depends on what you think looks best). Experiment with harnesses and what underwear you wear with your packer as well. Briefs or boxer briefs, for instance, are more likely to hold your packer close to your body (if you wear them over your packer) and can make your bulge smaller and less prominent.
As for STPs, virtually all the advice I could think of on that topic is contained in this article. I personally don’t use an STP anymore because I found it a little bit of a hassle to deal with. I just use stalls in men’s rooms, although I sometimes run into issues where all the stalls are taken or that there aren’t any stalls at all. I usually just try to find another bathroom in that situation and things have worked out fine for me so far. They can be really great for some people, though, so it might be worth trying if you’re curious.