Survey says that more than 50 percent of women clasp their bras in front, and then turn it backwards. This technique is incredibly easy, especially if your arms aren't as flexible, but it turns out that this method is technically wrong. According to an article published in Marie Claire, experts disagree with this approach because it stretches the bras fibers and shortens the life span of your bra. The advisable way is to put on the straps, and clasp it at the back.
But really, if your arms feel like breaking whenever you try to do the ~correct~ way, then go ahead and use the front-clasp method. Besides, no one's watching!