When would be the best time to have sex

💙💙💗Desiree💗💙💙 • Mommy of 2 boys and 1 girl 👦👦👑👣🎀They are my everything

My bf is always going out of town for work and we can barely have intimación. We are really trying to get pregnant it will be my 4th child and his 3rd if all goes well. Anyway today is cd4 of af and I'm wondering when will it be best what day should we try if we can't my whole f

ertile window. When should I start using opks?app says it starts Sept 8th what day would I have a higher chance and we're trying for another girl ...