Nasal sprays for premature ejaculation category of erectile dysfunction work within an hour to de-sensitise and delay response, prolonging erections for men who have a problem holding on long enough. They are not suitable for or intended for men who have difficulty in getting an erection.
These de-sensitising and delaying sprays contain a range of pharmaceutical drugs which reduce penile sensitivity so ejaculation can be delayed – ranging from antidepressants like Clomipramine to pain killers like lidocaine. (Delaying sprays containing pain killers are not nasal – they are sprayed directly onto the penis rather up the nose.)
Usually a prescription is required for these erectile dysfunction nasal sprays and they are not suitable for men who have difficulty getting an erection.
If premature ejaculation is not your problem you are better seeking more general erectile dysfunction treatment like oral drugs or herbal supplements.