Thor and Fandral capturing Jötun runt Loki, bringing him back to their camp because he's too pretty to let go.
Loki struggling as they feel him up; light, curious touches turning into groping beneath his robes. Cries and begs turning into confused moans as they brush over his crotch.
Fandral whispering sweet nothings into Loki's ear as Thor strips him, telling him that they would be gentle, that they would not hurt him, that after they got what they wanted they would let him go free.
They take turns with Loki, one holding him down while the other forces their way between the terrified Jötun's legs. Thor goes first; rough and harsh, making Loki sob when he bites his neck, claiming him. Murmuring threats whenever Loki tries to push him off.
Fandral being gentle with him in contrast, decorating his skin with soft kisses as he takes him, Loki being worked up despite not wanting this and despite how rough Thor had been with him, he ends up coming when Fandral is generous enough to give his cock a few teasing strokes.
Loki thinking it's over when he feels Fandral's seed inside him, limp and defeated as he asks in a trembling voice; "Can I leave?"
They don't answer. Not with words, anyway. Instead Thor retrieves some rope and they bind his wrists and ankles. Loki cries for them to stop but they don't listen. To let him go would be such a waste, they figure. He had felt so nice and they had never come across a Jötun like him. Why not keep him for another night? A few nights? They would needed something to look forward to when they came back from a hard day of battling.
And then, why stop there? Thor asks Fandral later, after they think Loki has exhausted himself with his struggles and fallen asleep. Why not bring him back to Asgard and keep him as their little pet? Surely his life here on Jötunheim wasn't anything special. Would it not be fun to have a Jötun slave; a toy for them to use and play with whenever they felt like it?
Loki, who is not asleep, hears all of this. And when he hears Fandral readily agree to Thor's proposal, and hears the two of them laugh and pass a bottle of mead between themselves, saying how lucky it was they had come across the pretty thing, he knows he isn't getting away.