I think you should approach it from a bit of a different direction. You should want a dog for it's own sake first, and consider the sexual aspects of it secondary. And realize that you are committing to a long term thing here.
What happens if you get a dog because of wanting "intimate experiences", and you then realize you don't really want that for whatever reason, yet now you still have a dog to care for for the next 10 - 15 years? Make sure you actually want to take care of a pet before thinking about the rest.
There is also no guarantee that your dog will want to be intimate with you, as they are all different with different personalities and limits for what they are comfortable with. Most of the time you can find something you both enjoy, but don't treat it as a guarantee.
As for what breeds to go for, it will depend on a lot of factors. Chihuahuas are very small dogs, and if you plan on your intimacy being anything more than licking, that is not really a good idea.
There are plenty of lists and articles out there for best beginner dog breeds that could could read up on. Labs and Goldens are usually high on those lists, and they are both very loyal and affectionate dogs.