My understanding is that there were two corkscrew manoeuvres:
1) Light corkscrewing along the general course to confuse radar-predicted flak and to improve the chances of spotting a nightfighter,
2) Evasive corkscrewing when a nightfighter was observed, both to escape and provide greater opportunity for the gunners. Although a violently corkscrewing Lanc can't have been much of a stable platform.
The night war over Europe became very confusing for all participants, heavies being hunted by a variety of Luftwaffe nightfighters being hunted by Serrate Mosquitos being (probably) hunted by Me262
Sunderlands could corkscrew to good effect, accounts of N/461's epic battle with 8 JU88s in 1943 are worth searching for.