Tonka, hay, tobacco.
This lactone is like the tippy top note of cream with a hay and tobacco note and more gourmand aspects than you'd expect given the name. Although of course it occurs in Angelica and some other green naturals, it doesn't smell green but instead sweet and herbal + coumarinic + tobacco + heliotrope etc. It also has an almost solventy booze note.
 
This isn't an 'unctuous' lactone: for that, try lactones from Gamma Nonalactone (Aldehyde C18) upwards.