"Seconding"

Term used for the wrestlers who wait on the other (usually senior) wrestlers in the ring and then post match afterwards. Their jobs are to take ring wear (i.e. robes and t-shirts), act as cheering squad, and after the match put ice-packs on and under the neck (never on the heart as this would slow blood circulation) and if needs be unlace boots and the back of masks. They will also escort (and at times physically carry) the seniors from the ring. After the match the trainees and the rookies will be expected to unlace their seniors boots, wipe down their backs, and fetch them anything they require. Rookies and trainees may also be required to do laundry, fold clothes and pack bags prior and\or after the match for their seniors and especially their teachers. 

The term is different to "ring attendant" (see below) 

Traditionally "seconding" was something that was done by trainees, rookie and junior wrestlers. The role can be performed by established wrestlers for another wrestler, as long as they are junior to them in some way. For example, Atsushi Kotoge seconded Go Shiozaki during his bout against Kenoh at the final night of Global League in 2017; while Kotoge is certainly neither a rookie, a trainee or a junior, he is both a friend and considered "younger" than Shiozaki due to both company position and length of time with the company.

In the All Japan days when the wrestlers used to have to run the gauntlet through the crowd, the seconds were expected to keep the crowd back by force and there were many incidents of people getting knocked aside with physical force. Mitsuharu Misawa detested this practice so much, that it was very rarely done in Noah, and especially not by him. 

Senior established wrestlers do not do seconding or ring attending. 

Ring attendants

A "ring attendant" is a junior or rookie wrestler (never an established one) whose sole function is to show the wrestlers were to exit to. These are the young people you see standing by an open gate etc with their arms outstretched. In bigger arenas they will be expected to escort the entering or exiting wrestler to and from the ring (plus holding the ropes open for them), but they are not generally expected to take care of them before or after the match. "Ring attendants" are also responsible (along with the seconds) of keeping the crowd back and away during spots that go into the crowd.