My LG has a dummy clip I attach to her baby grow or sleeping bag as she does this too.
Cold be becoming unwell, teething, going through a leap, could be cold, could be absolutely anything
@Emmz major strangulation risk
@Daisy hardly because it's a short one
Does she have any comforter aside her dummy, like my daughter has a little bunny rabbit 9/10 she sucks that and settles back down or she sucks her blanket.