Q. Where should I insert my penis during intercourse?

Hello doctor,

I recently got married and have a few doubts about intercourse. I am not clear about the vaginal spot. Where should I insert my penis exactly? I had a chat with my partner and she said that it is the spot where the gynecologist tested her uterus when we had a general check-up. Please suggest. Also, in the missionary position, I am able to insert easily but not in doggy or other positions. Does the position matter? During full erection, my penis is slightly bent downwards. In that case, which position exactly works out? When I try to deeply penetrate it is hitting or blocking at a spot and she seems to be quite uneasy. Also, do I need to release my sperms on that spot where it hits? Sometimes, post ejaculation and two hours after being in bed when she urinates some sperms come out of her vagina she says. Is that expected or do we need to deeplypenetrate? She is an O- blood group and I am B+. Being a third-degree relative to her, does negative blood group matter or block conception? We have been trying for the past six months and post marriage she got her periods early twice and only once she got her periods delayed. On all other occasions, she had periods regularly. Also, we have big differences in height as well. I am 5 feet 10 inches and she is 4 feet and 9 inches and weight is 79 kg for me and 50 kg for her.