Here is the full list of all 20 Frisky Business achievements.
Get all possible endings
Get it on with Jenny X4
No Wrong Answers in Trivia
Break the 4th Wall
Dated Jenny
Dated Balbina
Piss off Balbina
Collect every piece of evidence
Complete a play through with no sexy times
Be a Jerk to Sam and Charlie
Get it on with all the girls
Be nice to Charlie
Be nice to Charlie and Samantha
Get the true ending
Have Threesome with Jenny and Gertrude
Get it on with Claire
Get it on with Tiffany
Threesome with Balbina and Serena
Dated Lucy
Peep through all the girls windows