do (one's) bit
To contribute work to that of others in a group. If you don't do your bit with the slides, our presentation will never be finished on time.
do one's bit
Also, do one's part. Make an individual contribution to an overall effort. For example, You can always rely on Anne to do her bit, or I'm anxious to do my part as a board member. [Early 1900s]
do your bit
make a useful contribution to an effort or cause. informal The exhortation to do your bit was much used during World War 1, but the expression was current in the late 19th century.
do your ˈbit
(informal) do your share of a task, help a cause, etc: Everyone is expected to do their bit to make the business successful.In reusing this old paper I’m doing my bit for conservation of the rainforests. do (one's) bit
To make an individual contribution toward an overall effort.