If you're going to draw or commission ideas of other people's characters, please run your ideas by them first unless you're absolutely sure the character's owner would be okay with your ideas. I know you probably want to surprise them, but there's always a chance the character's owner won't be comfortable with the idea you plan to draw or commission for them.

I'm not targeting anyone in particular, this is just something I've seen happen many times. Folks like you and I are put on the spot when we receive finished artwork of our characters in situations we don't like, and only then are we asked, "Are you okay with this?" And it's difficult to say no because we don't want to make the artist feel bad for their effort.

There's always a risk involved when you decide to "surprise" people with gift art, especially when it involves fetishy or NSFW situations. It's better to not risk it and run your ideas by the owner first.