R.J.
You should NOT be able to feel it during sex, or any other time. In fact, about once a month one is supposed to feel around for the little bit of fishing line (not really, but similar, it's a monofiliment line that bacteria can't climb up) to make sure it's still there.
My HUSBAND noticed the line/string for about the first month. Not painful for him, just noticeable. Then it softened and for the past 8 years he hasn't been able to feel it at all.
Your flow goes back to whatever your "normal" flow is. For most women, that's heavier than on hormonal birth control. For a minority of women who bleed more on hormones, their periods lessen. For myself that means about 4 days. 1 SUPER heavy (about 1 super tampon per hour), and 3 days of very very light bleeding. (1 regular tampon every 8 hours... of course, I just use supers both times, because I'm to miserly/lazy to buy two different boxes). Sometimes I'll do 5 days... with the extra day being a more "normal" flow. (1 super tampon every 4 hours). And no cramping. Not after the first couple months years and years ago. Cramping just isn't a part of my personal cycle.
The most common "side effect" with paraguard is mega-cramping for the first 2-3 periods while your uterus adjusts to not being able to expel it. Midol, huzzah. And if Midol doesn't take care of it, an Rx muscle relaxer does. But the cramping is only on your period and in the very beginning.
I am one of those who absolutely LOVES my paraguard. I could have sex immediately (the day it was inserted and be protected), antibiotics don't effect it, no hormonal side effects, can't feel it, don't even have to think about it AND it has a lower failure rate than a tubal ligation. Love that.