Although I'm Japanese, I'm definitely American. I have a phobia about using Japanese "squat" toilets that are the most common toilet you'll find. Most places in Tokyo will have at least one "western" style toilet that I end up waiting for because I'm too chicken to use the squat.
Once upon a time, I had to use the bathroom on the drive home. The family stopped on the side of the road and instructed me to "go". Needless to say without being too graphic, I ended up all wet and never fully recovered from that experience.
Now that I'm all grown up, I still can't bring myself to use the squat. Especially in the winter! I was so afraid that I would drip on my pants, that I waited until a regular toilet was available. Yes, sometimes the wait is really long, but I will wait.
This is picture of one of the squats we saw in Japan. This one is kinda dirty because it was taken at a park, but normally they are very clean.
I'm amazed at how quickly Japanese women use the squat toilet. Several of them can use the toilet while I'm waiting for the one western toilet to open up. Still, I'm not brave enough to conquer the squat just yet.
For one thing I don't even know which direction to face! LOL! I found some useful signage online that illustrates the proper way to use the squat. I'm pretty sure I would have faced the wrong way.
It's times like these I really envy men. My husband is kept waiting for about 15 minutes for me because he is so fast and I'm still waiting. Oh well, never gonna happen.
On the flip side, the Japanese also have the most amazing automated toilet seats for their western style toilets! Our hotel room had these automated seats that heat, spray, dry, and even make noise so that others can't hear you. Now I'll admit that I was skeptical and intimated by the thought of using a bidet, but once you try one, you'll never look back. We liked them so much that when we renovated our bathrooms at home, we bought one toilet seat for each bathroom.
So, just be prepared that not all Japanese bathrooms have regular western style toilets. I heard that the more rural communities you go to, it is less likely they will have a western style toilet, so just be prepared.
Oh.. one last thought. In places like Akihabara, there are many people passing out tissue packs on the streets. I guess its their way of advertising... weird yah? Someone told us to take the tissue because sometimes when you use the bathroom, you may not have tissue and will need it. We only ran into them in Akihabara and haven't been to a restroom without tissue, so not sure how true that is.
Excuse me while I go mentally prepare for Japanese toilets for my upcoming trip!