I did it last month with the cup, since it's plastic it doesn't interfere, but i am fixing to O from my left side, the follicle was 3.5cm and my lining looked good, had a 2.35 cm also on the right but she was pretty sure the left one is the one that i wil O from. had about 4-5 follicles. Bad news though is that the donor will not be helping no more and didn't get a donation today, so hopefully some are still alive in there