Tuck in, to

l) Where reef points, slab, or jiffy reefing are used, one speaks of ‘tucking in a reef or even ‘taking a tuck’. ‘It was blowing pretty hard, and we had a couple of tucks in’, is the well-sounding way of saying that the first and second reefs had been made. Properly speaking, a reef is that actual area of canvas between two rows of reef points, and when that panel has been tucked in and tied down you have certainly ‘taken in a reef.

Tuck in, to (2) A seaman also tucks in a splice, and uses that verb where ‘make’ would be the ordinary word.