「順水人情」

(pos:名詞)
<explanation>
yue:順便幫人哋一個忙
eng:a favour which is convenient to carry out since it fits in with one's plans; literally, a favour with the flow of water
<eg>
yue:反正我都整緊呢類袋，幫你整多個都順手，當賣個順水人情俾你啦。 (faan2 zing3 ngo5 dou1 zing2 gan2 ni1 leoi6 doi2, bong1 nei5 zing2 do1 go3 dou1 seon6 sau2, dong3 maai6 go3 seon6 seoi2 jan4 cing4 bei2 nei5 laa1.)
eng:I'm doing the same type of bags anyway, just do a convenient favour for you to make you one more.