Peter had been tackled and manhandled quite a bit - today, even. That was just a natural consequence of being small and lithe while training with some real superheroes. He may be fast and rather clever, but if someone did manage to grab a hold of him… Well.
There were worse things than being wrestled to the grounds by training partners.
Wrestled to the ground by villains, for example.
And if Peter was honest - he wasn’t quite certain if Loki wasn’t closer to the villain end of the spectrum. His mind was a little foggy: Loki causing the NYC attack and Loki joining the Avengers and Loki pushing his tongue inside his mouth were all facts that were loosely swirling around his mind, not quite able to come to any solid conclusion outside of wow.
Loki looked like the cat that got the cream as he saw Peter below him like that. Flushing, blushing, breathing hard, his pupils blown wide in arousal. “So easy to impress…”, Loki mused. What a good little boytoy.