Working on some more Thaddeus headcanons because he's been a really hot ticket in the ask box since season two premiered, and literally all I can think about right now is how much I think he'd enjoy a "selfish" partner when it comes to sex.
Everything about the little dude screams "I have never had intimate contact with another human being and I will cry if I think I'm doing it wrong". He also doesn't seem the type to be super into self-exploration, so it's easy to imagine he's not very knowledgeable about what he likes, either. Sure, he has things he fantasizes about sometimes, but it's a much different matter when you have a real, eager person trying to give you what you want. It's more than a bit intimidating to him.
At first, he's mostly just looking for you to do some leading, to take his hand and show him where the two of you are headed. However, he finds himself really, really turned on if you're bossy about it, very explicit in your instructions. He doesn't know what he wants, and he certainly doesn't know what you want, so you giving him clear orders is fantastic in his eyes.
You want him to give you head for an hour straight? Just say the word. What position do you want him in? Describe it and he's already there, although he might be little red in the face. He lives to serve and make you cum. The ego boost it gives him makes him feel far better about himself than he usually does. He definitely has the makings of a free use kink with him on the "use" end. It would really tickle him to have someone be into him enough that they just decide they need him whenever, wherever. He's still learning, but he's an eager student.