What I do is run my finger firmly up the main stem, god, this doesn't sound right lol. and when I feel the place on the stalk which has quite a bit of flexibility I mark that as where I want to tie it down. Then I basically loop a noose/slip knot with some thin string around that mark and gently ease it down with my hand while keeping the tension on the string and then use some decent tape to stick it down around the edge of the pot.
I was crapping myself the first time but you soon get a feel for it it you use you hand rather than pulling on the string.
I wouldn't worry about the pistils tbh, it's all part of the cycle, many more white ones are bound to keep shooting up.