I don't get hornier based on the day of the week, or anything that is obviously time based and cyclical, though I'm sure it is cyclical. I do periodically go through phases where I am significantly hornier than normal, and that may last a week or two. It's not to say that I'm not horny when I'm not in that phase, just that I tend to get a lot more into it during those phases, I'm more likely to masturbate or have sex several times in a day, and I'm more likely to get more adventurous with my sexual activity.
I have noticed that if I spend a few days drinking, then on the last day when I'm nursing a hangover I tend to masturbate a lot. Often to a point where I might cause some skin irritation, and usually do not actually produce much semen towards the end of the run. I have nothing to prove this, but I think it might be the bodies way of dealing with a deficit of dopamine. I believe orgasms cause a release of dopamine, so it kind of compensates. Does anyone else experience that?