H2B is making a special trip down from his work (560kms north of Adelaide) and is having a sperm count (that he wants to do, but reckons he'll be embarrassed about doing so, fair enough me thinks).
When he comes down I'll be on CD27, and he'll be leaving on CD30. The sperm count will be happening on CD27...
I will be using an OPK. Should I just be guided by the OPK when to BD - or is there some other reason or logical time to BD?

(and on the OPK question - once you get a positive OPK -should you start BDing straight away?)