Whether or not you can “feel” the blood coming out depends on how heavy your flow is, and whether you are wearing a tampon or a pad. When you wear a tampon, you shouldn’t be able to feel anything coming out, regardless of how heavy the flow is. When you wear a pad or a liner, you may be able to feel the blood as it exits your body, but this typically only happens when your flow is fairly heavy. Either way, it should be painless!
Good question, because we all equate blood with getting hurt and feeling pain. When you have your period for the first time, it feels like there is liquid coming out -- not like you are peeing, though. Sometimes, because it is such a slight amount, you might not even notice. Other times you feel a gush, and then you might wonder, “Am I protected down there or is it leaking?” That’s the way it feels for me. Just so you know, I have learned that only about 1/4 cup of your period is actually blood, according to health experts.
If you’ve had your period long enough, you’ll most likely know just because you can expect what it feels like when it’s happening. I’ve had my period for about a decade (wow, nothing like a statement like that to make me feel old), so at this point I know it just happened or is happening. If you don’t already have a pad on or a tampon in, you’ll feel this sudden wetness in your panties. If you’re around the time your period is starting, you can pretty much assume it’s blood coming out (though if you’re lucky, sometime it’ll just be discharge). You can sometimes feel the blood coming out when you’re using a pad because your pad will go from dry to slightly damp. As you become more and more acquainted with having your period, you’ll begin to pick up what little things to look/feel for and you’ll get into a routine.