I have collected all 5 candles and have placed them on the circle. I can't perform the ritual though, it says I don't have everything required. I guess that I'm missing the gift. I thought maybe the anal plug was the gift but I guess not. I have the matchbook and I tried to light the candles, but that wasn't working.
But before getting to that scene, I haven't been able to trigger the sex scene with either Sam or Willow. I've given Willow the pack of smokes and she's in a better mood. I read somewhere that a clue to what she needs, is on the internet and I assume that was the hint about the empty beer bottle. I've tried asking about and giving her the empty bottle but that doesn't work. I have the dirty panties...not sure if they serve a purpose. I have the letter. I have the Demonomicon, I have the Poe book.

I'm sure I'm missing something simple...but I can't figure it out.

There's a specific command to start the ritual, something like "Perform the something or other ritual". If you read the book it should be in italics. For Willow, after giving her the cigarettes you need to find the roommate's gay porn magazine and give that to her.

As for the ritual, I'm pretty sure I typed the command just as it appeared in the book, but it's telling me that I don't have everything required...so I assume I'm missing the gift. Is it not the anal plug?

You put the candles ON the circle, not IN the circle. That was my mistake, at least.

Where is there lube, which would allow for anal with the succubus?

So where did you find the lube then?

The magazine is in the roommate's bedroom, you just have to 'search the junk' or something like that. Maybe search the bed or the dresser.

The lube (massage oil) is inside the shower in an bathroom (just open shower)and take it

Go into Damien's bedroom (the roommate). 'Examine' the bed and the magazine will be found