There was so much internal conflict involved in regards to his son. There was such shame in him having become pregnant with the octoped to begin with and yet, there was a different kind of affection he felt for this particular child of his because well... Loki had birthed him. It bothered him to watch Hermod slide off his son's back as if this were some common pony, and yet... Loki understood that Seipnir was a horse. A horse and child he had given to Odin. But Hermod was Odin's son, and it was infinitely better than that douche Baldr manhandling the Trickster's son.
So, he watched. He'd come to visit his son, give Seipnir an apple and ruffle his man... and fantasize about the day when he'd have normal children. At least, he hoped he'd eventually have normal children. That didn't change how he felt about Seipnir, or about Fenrir, Hel or Jorm. But still. His two older daughters were normal, as far as he knew, but he very rarely saw them.
Ah well, what would be, would be.
So he stood in the shadows and watched Hermod. Loki was pleased that the kid seemed to treat his son with respect and honor. Whether that was because it was Odin's, or because he wasn't just any normal horse, or because the kid may have had some unusual relationships with equines... Loki didn't know.
Tossing the apple in his hand up in the air and catching it again, Loki cleared his throat to let Hermod know he was there.