Having gone to the beach a few times in a swimsuit (Went fully exposed swimsuit only the last time I went, and before that was my first time going in a swimsuit without shorts or a shirt), I just wore tight, non-stretchy or very little stretch underwear, and I think it worked fine for me. The only issue I had was sometimes making sure the underwear under the suit wasn't show lol, but if you pull it high enough, it shouldn't be a problem.
The ENTIRE time, all i could think about was "they can see it, they know, they are looking at it, its so noticeable" despite my wife telling me "relax, you look like every other girl in a swimsuit. No one is looking at you.", it wasn't until i saw my pictures that I realized how much it didnt show.
I think it also helps to wear a black swimsuit, but that's just me. Black is both slimming and good at hiding many other things lol, Can't say its very comfortable to wear in hot weather though (absorbs a lot of heat). The swimsuit I wore was also just a liiiiiiittle bit tight and form fitting, which also helped to reduce the "bulge" >.<
Either way, if that's you in your avi, you look great already xD people will be too distracted to look down there in the first place :3 I was only 2 and a half months at the time of my outing :S talk about anxiety attack. If its worth anything; I didnt even have to really "tuck". Putting on the tight underwear and the swimsuit alone was enough to hide it, I can only imagine that tucking would have make it so legit that I could have fabricated an actual vagina lol. But i guess that really depends on the size of the boat
