1) To get this achievement you need to - On the second day, at the photo shoot to go with Robyn to drink coffee - have fun with her and drink coffee with "cream" instead of her - then later after yoga class you need to go after Erica in the shower room - have fun with yourself while Erica is taking a shower - and then Robyn will come and get her retribution
2) To get "True detective" you need to solve the riddle about who stole the golden dildo :P (I don't want to spoil this part for you)