Put the generated content inside a collapsible frame.
The frame is collapsed at the start.
By default, the title of the node is used as the title of the frame. You can specify (since 6-1.2) the title as the value of the parameter:
collapsed=There is my other node, click to read it;
See Also: Insert Node Parameter: collapsible (5-1.x) [no content]
IMPORTANT NOTE
Note that the parameter value ends with a semi-colon! Do not include quotes unless you want to see them in the output. Yes. This means the text cannot include a semi-colon as is.