Bit of research.....that rush of intense pleasure (point of no going back) is once the seminal vesicles are so full, the muscle holding it back (at the base of the penis) suddenly relaxes and cum rushes along the ejaculatory ducts - into the base of the urethra under pressue.......watch her face at 01.49! You can see the intense enjoyement as all that warm seed starts to gush into her penis and up the shaft.....It takes 2-3 seconds before it pours out. This girl is horny, because you can really 'read' her facial expressions and enjoy with her....