The tentacle scene is only available during the bad path events of Lace. You can't get that scene on her good path.
The reset for her events are only for the bad path, as the good path was added after the bad path existed for a while. The reset option is removed in the next update.
You need to have Leneth pregnant and find Hellhound with the maid uniform in your secret bedroom, before Hellhound will appear next to an opening in the vulcano of Amagal and lead you to her village.