She needs to go to sleep where you want her to stay asleep
Absolutely spot on. This is the problem here. Cosleeping is baby going to sleep where she stays asleep, just as baby going to sleep in the cot is going to sleep where you stay asleep. No problem baby going to sleep in your arms, if baby can stay asleep. asleep in your arms (for daytime naps).
The problem is baby going to sleep in your arms then upon stirring realising she is no longer in your arms and being freaked out by what's changed. The answer is to have no change in sleep position.
Transferring is awful sleep habits
True again. Those that end up cosleeping (rather than choosing to from the outset) usually do so because they realise that transferring is a problem - the usual difficulty of not being able to get baby into the cot after feeding to sleep. So instead they let baby go to sleep in the parental bed, where they will stay asleep. Which proves the point LoopThehoop made.
Kat160417: so are you saying its better to not hold them to get them to sleep?
OP: Yes, that is your problem here. Babies will usually wake and get upset when being moved once asleep.
So you could do with firming up in your mind if at night you want her to go to sleep the cot or in your bed and work towards getting her to go from awake to asleep in the place she will stay asleep.
"Work towards" doesn't necessarily mean it will be a quick fix getting it to happen. How quickly you get baby sleeping where she will stay asleep depends on your parenting style.
There are things you can do in the daytime to encourage better sleep at night, no matter what you choose to do at night:
- Get get baby going from awake to asleep in something that moves, this makes getting to sleep easier. Try bouncy chair or pushchair naps. Even car journeys if baby is exhausted.
- limit awake time to make daytime naps closer together. More sleep makes sleep easier. I'd suggest no more than 90 minutes awake between naps, with a slightly stretched 2h-2h30m awake time immediately before bedtime. Make the time for bedtime flexible according to naps that day.
- increase daytime calories. Either by making feeds bigger, more frequent or with less distraction. Try feed>wind>feed again.
At 5 months my day was broken into blocks of 2h-2h30m cycles - each involving one feed and one sleep. So wake, full feed, 90m awake time, nap, wake, repeat.