According to an article in Time Magazine, it turns out that there are a few problems with the spray-on condom.
First, there's the delivery system. "The prototype ... consists of a hard plastic tube with nozzles that spray liquid latex from all directions, much like the water jets in the tunnel of a car wash. ... Some (of the men testing the product) were 'a little bit afraid to use the tube' and would only try it on their fingers."
Second, there's the noise: "Others worried that the mechanism, which hisses as it sprays, might ruin the mood."
But the biggest problem of all is the waiting time. "Liquid latex currently takes two to three minutes to vulcanize, making it impractical. 'For people to buy it,' (inventor Jan Vinzenz) Krause says, 'it needs to be ready in five to 10 seconds.'"
In the meantime, manufacturers of traditional condoms have expanded the number of sizes available. But again, there's one problem: "men aren't very eager to buy a small size."
See? I did the whole posting without succumbing to the temptation to point out the "Hard Sell" pun in the article's headline.