Loki was bound in his son's entrails-turned-iron. He lay under a spring, but more immediately, under a snake that streamed venom. Sigyn holds a basin between snake and bound husband. When she empties the basin, Loki writhes from pain, and the Earth writhes with him.
A lull fell in their conversation as Sigyn focused on the venom-catcher, nearly full.
Loki was a trickster. The trickster, if you went by anyone Sigyn had ever known, anyone who had ever met the man. Anyone who had been around him for long enough to see one change on that exterior, one second looking wholly calculating man who was interested enough to help, the next smiling as it all tumbled down, clever enough to dance through the falling ruins without a scratch.
Sigyn thought of this, and also thought he had never broken his word. She'd always wondered if the other gods would ever figure that one out, that you merely needed to get his word and watch the wording--but then, of course, Loki was ever the trickster. He'd dance through the words, quickest, be just as free as he ever was, and smile when you realized it was your fault.
She smiled down at him the best she could. The snake dripped its venom on him whenever she emptied the basin, and she had long lost any hope of cleaning off what fell. She had learned enough of him, saw the tension in his eyes. He stayed silent through even the worst of it, sparing her ears or his throat. Only his attempts to break the chain gave him away.
The smile was weak, and by now Loki knew it to be her warning. She took the basin, quickly, emptied it to the side, then held it back above him, high enough that the first splashes out the side would harm neither half of the pair.
Sigyn was faithful. Any proper description needed to include that. She was loyal, and it still surprised some that loyal, steadfast Sigyn had chosen changeable Loki. Trickster, who would hardly ever bind himself to anything.
Sigyn would smile, and look at their sons--whenever they thought of them now, Loki flinched, or Sigyn bit back tears--and think, quietly, that changeable Loki was her trickster.
By the time Loki had been bound, no one was surprised to see Sigyn at his side. She had enough foresight to have a large bowl, and was faithful enough that leaving him did not occur to her. That fact was Sigyn, as surely as clever Loki was trickster and taunter.
Loki's pain echoed between them. She felt she should be able to do more, but any deflection melted, or fell, or splashed burning venom against him. Loki felt he should have been able to hide his pain completely, to have that much trickery in him.
Loki could speak again without screaming, without telling his Sigyn how much he hurt. The silver tongue returned, as did his playful smirk, though the tension never did leave his eyes.
He spoke a handful of soft words, borrowed from better times. She smiled at him, a true smile, and they laughed together.
When he shakes enough, the bonds will break, and Ragnarok will come. Until then, ever-faithful Sigyn dwells by bound Loki.