PGT
This story is inspired by an RP I recently got involved in over on Lolicit during ATF's down time.
So, in this RP, the idea is that none of the girls will easily accept sex and the MC will have to get them to open up in order to become receptive. It should take a minimum of a week for the girls to even be comfortable showing their privates, let alone sexual intercourse. (Of course, the magic of time skips as a literary technique can be liberally applied.)
This will be broken down into scenarios. Some scenarios have higher difficulty than others. You can also select the age of your own character, from young adult, older adult, young teen, and older teen categories. All scenarios are one male MC and one or two girls. (adding more girls will increase the difficulty by a large amount.)