There are many possible incest type scenarios possible in the world of DragonBall Z. This story will explore many of them. Some examples are

Chi-Chi and Gohan/ chi-chi and goten/ Bulma and trunks/Bulma and dr. briefs (her father) /Bulma and mrs. briefs (her mother)/ mrs. briefs and trunks/ Hercule and videl.

It does not need to be limited to one on one encounters either. For example:

Bulma with Dr. and mrs. briefs/ Trunks with Bulma and mrs. briefs/ chi-chi with gohan and goten.

I will write and post story threads and arcs as I am able. I encourage others to do the same.
So the first question is : Who do you want to follow on their sexuall adventure first?