tuck in phrasal verb ( see also ↑ tuck )
1 . tuck somebody in to make a child comfortable in bed by arranging the sheets around them
2 . tuck something ↔ in to move a part of your body inwards so that it does not stick out so much:
Stand up straight and tuck in your tummy.
3 . ( also tuck into something ) informal to eat something eagerly:
The ice creams came and we tucked in.
They tucked into a hearty breakfast of eggs.