This was the most challenging scene for me to unlock as well... Not because it is difficult to obtain but because it only presents on one of three possible paths...
Okay... That is Krista the prom queen. The girl in pink at the Pit, a club in Miltown. There are three possible ways to get to go to the Pit, with Sonja if you just want to blow the place up, grab Gloria and split; with Abby which will give you Krista's name and history or to unlock that H-scene you go with Ellen, the option marked "Friendly Face."
Go to the Pit with Ellen, the easiest way to get in with weapons intact is to go right and take the option to hide in the crate. You shouldn't actually need the weapons anyway so before heading right I always stash my weapons in the vent by heading left first, stash weapons then heading right and hiding in the crate. Once inside, head toward the music. Mill about, talk to the dancers and you will eventually meet Krista, all dressed in pink. She will proposition you for sex. If you go have sex with her you loose a score point with Ellen. However, save before you say yes to Krista, play the scene to unlock it in gallery then reload to before the choice and tell her no thanks... no score loss with Ellen that way. Hope that helps.
Adventure ever on my friend, Phat
