There’s some ripe softcore silliness here from veteran horror screenwriter Dennis Paoli and director Joe Lynch, inspired by HP Lovecraft’s 1937 story, The Thing on the Doorstep. Despite a very game lead performance from Heather Graham, and some amusing 90s-style erotic thriller mannerisms – voile curtains blowing on a hot summer night while a sex scene happens to a wafting sax accompaniment – this left me not knowing quite where to look.

Graham plays the entirely preposterous psychiatrist Dr Elizabeth Derby (gender-flipped from Lovecraft’s original male protagonist), professionally fulfilled and happily married to devoted middle-aged hunk Edward (Johnathon Schaech), who cooks her branzino in the evening and spends a lot of time with his shirt off. One afternoon, Dr Derby has to treat a disturbed young man called Asa (Judah Lewis) who has what appears to be dissociative identity disorder. But, in fact, he is genuinely possessed by a malign demon, in whose control Asa manages to seduce Dr Derby and then invade her body during sex.

These wacky body swap transitions are signalled by the people involved doing much shuddering and gibbering, and Graham does a lot of eye-rolling crazy person acting during the subsequent scenes. The parts of the story involving Asa’s elderly father (Bruce Davison), whose character is also possessed, feel a little extraneous and – generally speaking – the comedy involved is probably best described as semi-intentional.

• Suitable Flesh is released on 27 October in UK cinemas and on digital platforms.