ok, been doing the opk four times a day, since i have an extremely short lh surge (6-12 hours). last night at 7 it was negative, but i knew it should be soon, so at midnight, we bd. this morning at 8 the opk is +. i will continue to test, but expect the surge to be gone by noon today. so bd tonight still? or was last night my only chance (which, thankfully, i caught)?