Something that is free-flowing is able to move without anything stopping it.

free-flowing rivers 自由流淌的河水

free-flowing traffic 畅通的交通

happening or done in a continuous and natural way

a free-flowing discussion 畅快的讨论

a free-flowing style of playing the piano 行云流水般的钢琴演奏

easily available in large amounts

There was free-flowing champagne at the party. 派队上有大量的香槟酒可饮用。