On 28 may we intimate. I just simply rub it and do not put it inside.But while rubbing my penis slightly goes inside and on the same time it came out just a small portion of penis inside for a while and no strokes. We say not more tha 5 sec. We do not take any precaution while this. When my penis goes slighty inside then she had bleeding just a droplet of blood or a small spot of blood nothing else. And after this within 3-4 hours she takes ipill. But she gets period 4 days before the regular. And she had pain on the 2 day of menses as well but previously she have pain on first day only. And colour of blood is slightly brownish in starting and then red on the first day of period and then for rest of days red colour blood. And brownish colour blood also happen in her previous periods. Her days is usally 5 but this time only 4 days of period. And flow is lighter as compared to previous periods. Is there any chance of pregnancy. If it so then how to avoid it.