Tactusa flexus is a moth of the family Erebidae first described by Michael Fibiger in 2011.

The crosslines are absent, except for the relatively broad white-beige subterminal line and a terminal line marked by black interveinal dots.

The reniform stigma is almost invisible and beige, outlined by a few brown scales.

The hindwings are unicolorous grey, with a discal spot.

The biotope consists of moist, mainly broad-leaf forest with shrubs and herbaceous plants, close to a river.