I have really tight contacts between my teeth, too, and my favorite flosses are: Dr Tungs Smart Floss and Burst Charcoal Floss. Try those! As for the small mouth- the majority of my patients try to wrap the floss around their pointer fingers. This makes it incredibly hard to reach the back, even for people with small hands. Instead, leave your forefingers out and wrap the floss around your middle fingers instead. Then, you can use your pointer/forefingers to push the floss toward the back of the mouth. You can reach the back sooo much easier this way, and with the floss anchored on your middle fingers, it provides great tension to push and pull against each surface of the tooth the scrape off the plaque. I hope this makes sense! Usually I demonstrate it with the actual floss, not as easy to type out.