Take heed to Mushroom’s post. An erection starts in the brain. If you’re mind is in a panic mode, your dick is not going to respond.
Guys need to be very careful with PE, realizing how badly it can affect the nerve sensitivity. A dick is not made to be constantly rubbed on vigorously by our hands or whatever other devices men will attach to it to make it bigger. Ultimately, a pussy is meant to be the only stimulation for a dick. But we whack it, rub it, and attach all kinks of devices to it until a pussy no longer feels very stimulating. If we’re not careful, we’ll slowly train our dicks to respond only to the most extreme stimuli.