Some people say once every two days. I usually BDed every night around about this period! It's up to you! However, when you get your positive OPK, this signifies that you will ovulate from 6 to about 36 hours later. So BDing when you get your positive OPK would ensure that sperm would be in your body when the egg is released.
Don't worry about not getting a clear result, even if you have bded a few days before ovulation, sperm can live for a few days in the body.
Good luck - here's some baby dust!
