Sesquiterpene alcohol synthase that catalyzes the formation of (1S,6S,7R)-sesquipiperitol, a terpene intermediate in murgantiol biosynthesis, a male-released aggregation pheromone. (2E,6E)-farnesyl diphosphate + H2O = (1S,6S,7R)-sesquipiperitol + diphosphate Binds 2 Mg(2+) ions per subunit. Pheromone biosynthesis. Specifically expressed in tissues lining the cuticle of the abdominal sternites of mature males. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.