I personally only bitch at a guy when I'm finished with him..I know it sounds harsh but its true. I feel horrible when a guy really likes me and I don't like him so I bitch and I nag and I do dumb things to make him not like me. If I like a guy I'm extremely sweet to him and only after we've been dating forever will I bitch constantly but I always apologize and usually find someway to make it up to him
To answer your question Niger girls have peaks of sexual energy right before and after their periods..I know it sounds gross but from a scientific stand point the heigtened level of estrogen during that time is what causes the "streaks of horiness" so if you're wanting to get laid right before or after the period you're golden! Also you have very little chance of getting pregnant then too.