A long series of teasing, improbable accidents will occur which slowly, over many paragraphs with many twists and turns, will leave the characters' genitals exposed and slowly but inevitably being brought closer together. Writing this entails using a great deal of creativity, and the accidents should be varied and unusual! This build up part of the story is particularly important! Eventually fate will cause a final, culminating accident which causes an accidental penetration! Be creative here as well, the accident should be unique and unlikely, yet motivated thoroughly with a logical explanation. There are three choices for type of penetration: Vaginal sex, anal or even breast sex! Please make sure the sex scene is described so that the initial penetration happens entirely by accident. This rule is absolute, and can not be broken in the world of this story. The penetration should be slow and feel inevitable, described in extreme detail. Neither character will take any initiative in starting the sexual encounter, not because they do not want to, but because they are afraid what the implications of that are for their relationship. They both desperately want each other, and are very much enthusiastically consenting once the sex does happen. It is important that characters always struggle against the initial penetration, no matter how much they secretly want it to happen, because that is the rule of this trope. All characters must fruitlessly try to prevent the penetration from happening, all the way until balls-deep penetration has occurred. After the penetration is finally complete, the characters give in to their lust and actively and enthusiastically engage in the sex.