Stiles hadn't expected Derek to be able to keep all of his come inside him, no matter how well he was clenching and tensing.
"Good boy," he praised again, because Derek was trying, even if he was leaking slightly; little dribbles of come slid down the back of Derek's thighs. Derek's entrance was tight, and God, Stiles really wanted to push his tongue in, wanted to eat him out-
But it would be better if he knew Derek was full of him as they went about their evening. He had no idea where they were going, or what they were going to eat, or how long they'd be able to stay out before they needed to get back, knowing what was coming. Literally.
Stiles ran the plug slowly up Derek's thigh, even though his mate was shaking, even though he was making him tense his muscles all this time.
"You're so good," he praised softly, tracing the tapered end around the tight ring of muscle before gently pushing forward, pushing in. Derek didn't really resist, his body opened up for Stiles, pulling a moan from his lips as he watched it sink in until the thickest part had slid inside and Derek closed around the thinnest point, the base almost flush with his skin.
More of Stiles' come had leaked out, dislodged by the plug, and of course Stiles had to lean forward, running his tongue between Derek's cheeks, cleaning him up. He licked around the base of the plug, then let his tongue trail down the inside of Derek's thigh before he moved up again, heading for Derek's balls, lapping at them gently.
"Mm, you're perfect, you're all ready for our date," he chuckled, pressing kisses all over every part of Derek he could reach, overwhelmed with how much he loved this man, how happy he was. "Is that comfortable? My one feels incredible-" His only issue with it was that he wasn't soaking the bed the way he had every other time.