Depends.
How close of friends are they? Does she reciprocate his feelings? Is this chick monogamous, promiscuous, or what? Etc. There isn't one standard reaction for this kind of situation. For example, most people I know would be absolutely disgusted by the idea of pity sex.
Maelstrom
They're very close friends, and she doesn't have romantic feelings for anyone other than her boyfriend, though she knew (and very possibly had some feelings for) him prior to her current boyfriend, who at the time she had been going out with for almost a year or so. She's monogamous, most likely, but is perfectly comfortable with the idea of sex.
I'd say the most important thing with this situation is that she's very depressed, but denying the very true fact that she needs someone at this point. She doesn't want to admit it, but she's very dependent on other people, and not just in this scenario. At this point, she really needs someone to comfort her, and so her friend comes in with his own brand of "comforting", that she agrees to. Though she might not be in the best state of mind for this kind of decision, and feels pretty horrible about it afterward.
I write pretty good fanfiction, sometimes.
It looks plausible... although the way you word it makes the guy sound like a total creep, was that your intention? ^__^;
Maelstrom
He's pretty much powered by lust at this situation. She's really hot, and he wants to have sex with her. He does have some honest feelings for her, more so after the act, which makes him not completely feel perfectly right about it afterward.
Yeah, he's kind of a creep, indeed. Though, like everyone in the story, he's presented many ways. Of course, his friendship with a lot of the characters is very, very fractured later.
I write pretty good fanfiction, sometimes.
"That chick was really hot!" doesn't really make him more sympathetic...
I take that you'll be showing the consequences of what he did, if his relationship with the other characters goes sour eventually?
edited 1st Nov '10 11:41:50 PM by melloncollie
Maelstrom
Not really supposed to. 
She'd probably try to lie to herself about what was going on, and when the lie breaks down, that's when it'll really affect her.
If I'm asking for advice on a story idea, don't tell me it can't be done.
Maelstrom
Yeah, the guy is pretty much reviled by the girl's boyfriend. In the present timeline of the story, though, the uninvolved characters that are in the group of friends are over it, and the guy has tried to make up for it. But then again, nothing good happens to him in the end.
I write pretty good fanfiction, sometimes.
Zzzzzzzzzz
I read that and say "where is her boyfriend during this time that she's so vulnerable?" You need to have a very good reason for him to be out of the picture if you expect it to be convincing that she would get it on with this other guy.
...if you don’t love you’re dead, and if you do, they’ll kill you for it.
Maelstrom
Yeah, he'd have to be out of the picture. Given that the guy is the son of two prominent businesspeople, he could likely be away with his parents on some business trip, as I could say his parents want him to follow in their footsteps and all. Oh, and the characters at this point are around 17-18, in high school. Grade 12, probably.
I write pretty good fanfiction, sometimes.
Street Writing Man
I'd watch it with the whole concept of pity sex in general. Its one of those touchy-debatable ideas that will divide anyone who reads your story. If you want it to be a bone of contention go for it; but bear in mind that people will pick apart that scene.
Myself, I wouldn't do it. But not having read the scene or the story it goes with I can't say further than that.
If I were to write some of the strange things that come under my eyes they would not be believed. ~Cora M. Strayer~
NCC - 1701
Well, I think only you can answer that question. I know, I know, that was a trite answer.
But seriously, you can create a character who would believably do something like that. I think the big crux is girl's current boyfriend. If he doesn't seem to be able to help her in her grief, then yes, absolutely she might very well go for sleeping with someone else.
People have sex all the time to escape the things they're dealing with. And for reasons a lot less dire than the death of a parent.
It was an honor
I have a situation where two characters have implied pity sex, a scene that's actually in backstory, but has a lot of relevance to the main story.
In this situation of which I am describing, one character has undergone a lot of grief (her father recently died) and she keeps away from other people, even her friends, but can't bring herself to admit that she needs their help and sympathy. She wants to deal with this herself, to the exclusion of everyone else. Enter one of her friends, who has had a major (mostly sexual) attraction to her for a long while. He hasn't been able to act on this because she's going out with another guy, who she's very much in love with. I'm wondering, would a person like her agree to this? If so or if not, what events could lead up to this, or what kind of dialogue would be involved between the two, mainly on the guy's side?
I write pretty good fanfiction, sometimes.