Im wondering if its safe to rock your back and squeeze both legs tight to reach orgasm during 7 months or in any months of pregnancy? I am on my 7 months of pregnancy now and still doing it,makes me feel good for a few minutes but makes my belly really hard and hard to breath after... I want to know if am I hurting my unborn baby inside me doing this or just safe? Thank you.

Unless your doctor suggested that you refrain, reaching orgasm while pregnant is perfectly fine.
The tightening of your belly from an orgasm won't hurt baby.