Being on happy is not enough you have to make specific choice during the previous updates...Am need more info lol cuz I've done this a couple times sam not mad at all so idk what am doing wrong also am on the happy path
First you need to be on a very lewd run.
when Liz ask you to go shopping you after the camping trip, have to let her go with Sam then pick every nts option you can 'find hot when oogling, make her wear a revealing dress, make her tease, let her drink more)
At the university suggest show skin as pointers and let her stay with the students.
Then make her wear a short skirt at work.
On prankster day let her meet Sam when Sam ask you tell her it is your idea, and let Liz confirm.
At the beginning of 0.19 part don't meet Liz and let her go with Sam again