Are you trying to let people know you're a generator of superior fecal matter? If so, there's no need to apologize for it. Carry that stuff with pride.
Everyone's gut is different, but one minute isn't unreasonably short, especially if you have something like a bidet for fast cleaning afterwards. Are you sure you're not constipated?
Sure, but the actual splash act just takes a minute at most, and usually about 10 seconds for me. I don't understand how you can have time to read anything.
You're getting your book dirty for what is, as far as I can understand, no real reason. Why not read your book after washing your hands? (If you have a severe chair shortage, then sure, I can sort of understand: sitting to read is pleasant.)