from a non-pharm standpoint, look into tantric sex. Some guys are able to reach the point of climax, back off, and then take a quick pause (literally a pause, or do other things) and then perform for an extended time afterwards. To be honest, with practice this is easily achieved and can become commonplace. It isn't withholding an ejaculation, as it is beginning to understand how to move beyond the premature feelings of ejaculation.