Into the multiverse with my ever growing harem

One day a screen appears in front of Sagi, a normal high school student, and asks him if he wants to use the Knock-up ticket to have sex and impregnate the beautiful and big-breasted school girl who is traveling with him on the train. Seeing this once-in-a-lifetime chance to have sex with such a pretty and buxom girl, our protagonist has of course only one answer. "What the heck? Are you crazy?! Of course NO! Why would I do something so stupid?" However, the screen in front of him keeps being extremely persistent. [Comon buddy, this is a once-in-a-lifetime opportunity! You are thinking with the wrong body part!] [Comon bro, you can't be doing this to me! We cant start the plot and PLOT without you!] [Comon you virgin beta loser cuck, do it!] [I swear, if you don't click YES I will send your Loogel search history to everyone you know!] [Would you do it if I give you a cookie? :D ] Little did he know that that was just the beginning of his adventure to become the harem king by traveling the multiverse and impregnating busty beauties.