I've tried clipping my bonnet to my hair with small duckbill clips, but eventually I just resolved that if the cap falls off, it falls off. I'd have some nights where I was constantly fearful that my cap would fall off that I didn't get a good night's sleep. Seriously.
I've also had the opposite problem, I have a large satin sleep cap that fits too tightly around my head that it often gives me a headache.
I'm considering getting a scarf to wrap around my hair when I pineapple, because I think I'd get better results that way and worry less about it falling off.
Curl Style: 3b/3c
: Giovanni TTTT (my hair loves this)
: GVP CB or DevaCurl One Condition, occasionally with honey
: Biotera Styling Gel, BioSilk RHG
: AG Re:coil, CJ Beauticurls, Lube
Hair hates Aloe Vera & Avocado