Gen query for conceiving. This window?

Thank you for your question. There are a number of factors to consider when attempting to conceive. If you have good quality sperm even a drop of semen is good enough as it contains millions of sperm that immediately start swimming to the egg. Naturally the sperms closest to the cervix have a better chance. So there is no issue with washing semen off the external genitals provided you ejaculated inside her vagina and some of it flows out. The second aspect is having good quality eggs. If the periods are irregular it means the eggs are also not released in every cycle. Generally ovulation occurs fourteen days prior to the first day or the next period. It is difficult to judge a window of ovulation if you cannot predict the date of menstruation. Generally therefore gynaecologists say just have sex regularly. I.e every other day and that should be fine. The egg survives for up to 48 hours while sperm can survive for up to 7 days in the genital tract. Nowadays you can buy kits to help you determine the day of ovulation. Please ask your gynaecologist for help with using these. They can also check if your wife is ovulating OK and your sperm count is good. best wishes