Right, where is Sir C.

[Burney]

As in "Alfred Wainwright narrowed his eyes and surveyed the fellside for a gully into which he could discretely sneak in order to update his logbook"?

Precisely, a. A perfect example.

Although it needn’t be restricted to masturbation. It could also be defecation.

‘Through a haze of rough cider, brandy and regrets, Dorset became dimly aware of a warm, viscous sensation that could mean only one thing: he had updated his logbook’.