Bittersweet smut! There's an edge of sadness around the hotness - as much as Ianto is relishing the experience, he's burdened by guilt - he wants Jack, but that means he's betraying Lisa. Poor Ianto, starved of simple human contact for so long because of Lisa's condition that Jack's concern completely undoes him.

I suspect I shouldn't be thinking so much after reading this, so now I'll just crawl off to my bunk and turn my brain off ;)