Copper
"BEST FORM OF BIRTHCONTROL
I got the copper iud 2 months ago because I couldn't cope with the synthetic hormones from the pill. 
The insertion was painless, I was put to sleep and woke up with mild cramps for the same afternoon then no other pain since which is strange because in the past I've experienced terrible period pain!
My period is not heavier, its just different. The first side effect I noticed was my discharge is really clotted and snot-like which is weird but tolerable.
When I got my period it wasn't a thin brown flow like it normally is but rather it was the same thick discharge but more of it and very dark brown. 
My boyfriend has not noticed the strings during sex aswell which I was also worried about.
I would 100% recommend it!"