Terrence probably should have made a move to defend himself, but all he could do was laugh at the expression her face. His hands came up to warm themselves in her hair as he kissed her back hard, not caring if he got hit with the snowball. He did attempt to distract her, though, as his hands moved down her back (would have raked his nails down, but she was still too well clothed at this point) to her arse, pressing her hips hard against his.
What followed was one of the coldest hot moments of his life, since he couldn't be bothered to pause to cast any spells or even arrange their clothing on the ground beneath him once they'd gotten past the snowball fight and down to appreciating each other's bodies. But thankfully they didn't get entirely undressed for the experience, so he didn't think any of his parts were going to freeze off.
It still seemed utterly ridiculous to him, though, after he'd found his glorious release, holding her close and cooling down: so ridiculous that he started to laugh, breathlessly. He lifted his head to kiss her, twining his fingers together around the back of her neck, and then smiled up at the snow-laden branches above him.
"Definitely want your soul inside me," he said breathlessly, and then started laughing again. He felt giddy from his hysteria earlier, the adrenaline of the fight, the afterglow of an incredible shag, and most importantly, the idea that he would soon be her horcrux, and she would soon be his. Still laughing, he shook his head at the ridiculousness of it all and added, "Fucking hell..."