Anyone did any nap/sleep training?

Ren
Anyone did any nap/sleep training? No shushing, rocking, swing, mamaroo, boppy & co sleeping. How old was your little? How long did it take? What method did you use? My little is allergic to sleeping on her own. She will only sleep if someone is holding her. I'm not opposed to the CIO method either. Any suggestion/tips will be greatly appreciated. Please be nice, I know this is a controversial subject & a touchy one. Thanks mamas!! 😘💕