Term used to describe a situation where a man fails to sustain a pre-existing erection. Often applied to instances where sex was imminent but did not occur as a result of the flopped straight.
Note: "flopping a straight" can have multiple connotations. In poker, it refers to a situation where a player makes a straight using the first three community cards (the flop). In "poke her", it retains the above definition.
Mike was so horny after making out with his girlfriend for three hours, but when she took her panties off and he finally realized he was about to lose his virginity, he got so nervous that he wound up flopping a straight, much to her dismay.