Ladies, Please oh please do not think that tape or sports bras are your only hope!
Take a cue from the transgender community, and use a binder. "What's a binder?", you ask. Oh-ho-ho, binders are not just for school anymore! They are super stretchy double (now sometimes triple) layered spandex & nylon shirts (essentially) that compress your chest and torso.
Check this beauty out!That particular model is actually a new version of a classic binder, with extra compression for the chest (for female->male transgenders). They also work wonders for crosplay as well; I have converted at least three of my friends into using them for just about any (sans open-shirt) crosplay! Binders are really going to be the most comfortable, effective, and (in many cases) safest way to bind. If nothing else, they are certainly the easiest/fastest binding method.
JUST REMEMBER: step into the binder, instead of trying to pull it over your head. [/infomercial]