According to the packaging you shouldn't use first morning or evening urine to test with your OPK which, for me, means I have to do it at work . . . in a public restroom.
It's all well and good to pee into my Gü ramekin, leave it sitting on the shelf for half an hour to cool down, dunk my OPK, leave the stick laying around and read the results five minutes later at home. At work, not so much.
How do you working girls do it?