How to press more buttons?

Genuine question. I've noticed, that I lose a lot of games because I am turtling too much and I let opponents get away with pressing into me freely. A lot of the time I am just waiting for the opponent to go into me because I prefer side step heavy defense in neutral. As a result, I am getting hit by a lot of mixups both in neutral and on wake-up. I freeze up a lot and I eat all the mixups basically, which leads to me losing and getting angry. How does one find balance between mashing buttons and turtling, so that it doesn't make me lose even more, than I am already losing?