Can We Do Sex In Sixth Month Of Pregnancy?

Most certainly (unless the doctor says no). You just have to pick a position that works for both of you, and is not uncomfortable for you. The baby might become active during sex, so be prepared for the distraction. On your back with the man on his side works well. All fours works with a pillow to support your belly. You on the bed on your back, and him standing works good too.
Have fun.