My arms? Oh dear, i can't tell if that's good or bad x) I'm very self conscious about my lack of tricep muscle lol. Thank you though!
For Lukas, It's comfortable with the understanding that it's crunching your breasts to your chest lol =D In all realness though, I've used Ace (worst idea ever), duct-tape (Again, BAD), serana wrap (awesome form but gets way too hot) and tight clothing (excessive bulk and did nothing since I have such a big chest) and I have to say this binding is the best. Because it stretches I can expand my chest completely to breath nice and deep, and because it is the right size, but meant for my stomach, it does not constrict the rest of my body but simply feels like I have a snug tank top on (under my breasts). For my breasts in general, it is tight but if you adjust for comfort (instead of the look, which isn't noticeable if you wear a big tee on top) there's no pinching or any pain. Just a nice tight fit ^_^ I had to wear it for three days straight once, only taking it off while sleeping and I never developed any redness, scratches or bruises =)
It's called a Cupid, mine is a size medium, which is a size smaller than I probably would have bought. So my mom bought it at Walmart, i'm pretty sure you would find it in by the bras, heres a better picture of it.

The only downside to me is that it is very difficult to put on unless you have a strong upper arm. It's very tight as it goes over your shoulders (at least for me it is, but i've got broad shoulders anyways) and a bit difficult to figure out once you get it around your bust, but despite the difficulty, in my opinion it's worth it. I believe it was only about 30$ as well.