Can't remember the name but would love to know

There is a manga that has two childhood friends and some day they had sex and then after that they found out that there was a baby in the house that the sister of (not remembering what to call then just to tell I would call this character Oka) left and asked him to take care of him and if she didn't find out What he did with his boyfriend was so he decided to keep him and there was a situation that the baby was trying to take milk from the ova's nipples and he must have been pitiful and his childhood friend helped him If anyone knows the manga I would love to know thank you