Hi, welcome to the forums :)
I'll start off with telling you about my contraceptive history. I have tried three different types of pills, the implant, and the contraceptive injection and none of them have been good for me. I've always either had a very low libido, put on a lot of weight, or generally just been very unhappy and not felling like myself. I decided after my last pregnancy that I wanted a contraceptive that didn't put hormones into my body, I wanted to feel like myself, and be myself! So I enquired about having the coil fitted.
I found out there's over 10 types of coil that you an be fitted with, so it's best to go and see a healthcare professional who can advise you what you would be best suited with. I was asked about previous contraception and why I made those choices. Basically, I had really really heavy periods that would give me horrendous cramp and I wanted something that was easy! So I was given the option of the Mirena coil. The Mirena coil also releases hormone into your body, but it is just a very tiny amount around your reproductive organs, so you're not having a high amount of hormones into your blood stream like other contraceptives. This hormone makes your cervical music thicker when you're ovulating to make it harder for sperm to get through, it also makes the lining of your vaginal wall very thin so an egg can't attach to it. This therefore makes periods very light, sometimes non-existent, because that lining of the womb is your period!!
I had my fitting done when I was on my period!!! Embarrassing! I started that day so went to the appointment anyway, and told them I was on my period so I can't have it done. They said no no, this is the best time to do it!! So I had to have it done! To be honest, I'm glad I went ahead with it. There was two ladies that did the procedure, it was totally pain free and very quick. They chatted to me all the way through and made me totally relaxed, it was so so easy! For a couple of days after I had a little bit of cramp, but I think that was just because I was on my period anyway.
Since then, every period has been pain free and no where near as heavy as it used to be. It hasn't affected my sex drive, or weight and I have felt myself all the way through.
The 'strings' have never ever gotten in the way with sex toys. The strings are actually metal wires, but they're so high up inside you they're really hard to feel. Your cervix moves up and down during your monthly cycle so it's easier to feel them at certain times of the month, and you should check them regularly to make sure the coil is still there. So when you're ovulating, your cervix will be very high up, and it's hard to feel the strings, but just after a period your cervix is very low down, and very hard so it's easier to feel the strings.
We've never had any problems with them, but my husband has mentioned that sometimes usually before or after I have a period he can feel the strings on the tip of his penis, but it doesn't bother him, he just notices that they're there.
The strings are seriously so high up, most of the time you'll never notice them. I've got countless sex toys and they've never gotten in the way, it's honestly not a big deal in the slightest.
I also go to the gym 4/5 times a week and I've never had any issues with it. I can't even feel it, ever! I always wear tampons when I'm on my period, and it's never an issue either.
I'm really happy now I've found something that lasts for such a long time! It was so annoying going for injections but now I don't even have to think about contraception for five years at a time! Amazing!!
I'm worried that you might have heard too many horror stories because of some of the questions you've asked, but you must remember everyone is different. You could just try it out, and if you don't like it have it removed. Personally, I think every woman should have a coil. They're amazing and definitely not as in-the-way as you think they would be!