There are a few things that I have trouble with when it comes to this line of work. One of those things is ducks, a strange conundrum that I'm still trying to reconcile. I don't find ducks sexy, and yet (for some reason) ducks are a favorite animal for anthropomorphized "funny animal" cartoons in by Disney, Warner Bros., etc.
Now, when I say I don't find ducks sexy, the main thing I'm talking about is their lower half. The duck legs, and strange bulbous hips are difficult for me because I don't know how to use them. Additionally, there's the beak, and between these two parts of the body 99% of the potential poses for an erotic image are suddenly limited. I have no idea how to make a duck blowjob sexy. Likewise, any form of penetration is going to present challenges for me. I did a lot of research on how other people have drawn ducks, and a lot of them involve things like giving human musculature to the legs or basically just painting duck colors on a human body, which I feel is taking the character a bit too far off-model.
That being said, there are a number of duck characters who are sexy that pop up because, again, ducks are a popular animal in cartoons. Tina Russo here is probably the best example of a character who, through a variety of qualifications beyond her species, I find extremely attractive. So, to try and find reasons to draw her, I have to think of different options. In this case I landed on a hand job with a cartoonish facial (with probably the only way I can think of to make a duck bill sexy), but hopefully I'll be able to figure out other ways to use her without having to go too far off-model.
And don't even get me started on Daffy's cock. That was an entirely different concession, because there's no way in hell I'm using an anatomically correct duck penis in a picture like this.