In itself Viagra is a purely physical remedy. Its only effect is to improve the bloodflow to the penis, thereby enabling stronger erections. It does not, nor is it intended to, make you feel randy, and the manufacturers (both of Viagra and of Ciallis and Levitra) state categorically that it will not produce erection unless some additional form of sexual stimulation is present - this, of course, can be either with actual contact with an object of sexual desire, or simply mental anticipation of sexual action by thinking about it.
What causes the apparent psychological benefit is not the Viagra itself, but merely your belief in the effectiveness of viagra - you believe that having taken it you can now perform satisfactorily, so you do just that and it boosts your ego; however, without any additional sexual stimulus by either thought or deed the desired effect will simply not be achieved.
The effect notice by Yorkshire - prolongation of the time before emission occurs is quite common after taking viagra. The manufacturers of all the three drugs warn of the risk of priapism (i.e. an erection which refuses to go down again for many hours or even until medical attention is sought). What you experience is simply a slight touch of this effect and very often the penis will stay erect as long as intercourse continues - if you really want to impress your girl take this opportunity to give her several orgasms on the trot, she`ll think you`re terrific.
How many times you can `pop` is not affected by the Viagra, but depends on the productivity of your prostate gland and how quickly it can manufacture another load of seminal fluid.
