"There are two ways to conceal a boner: the wrong way and the right way. Which method you choose depends on whether or not you're comfortable letting other people know that the cadaver isn't the only stiffy at the funeral.
The Wrong Way
The wrong way to conceal a boner almost isn't worth mentioning, because all men have tried it, and all men know it doesn't work. The method is simple: just bend over. The problem with this technique is that bending over draws attention to you. You might as well stand on a chair and shout, "Hey, look at me, I'm a fucking psycho!"
The Right Way
The right way to conceal a boner is to cover it up with something. A newspaper, a jacket, or a family pet will do. If you don't have anything to cover it with, try going on to the offensive when confronted. If a woman inquires, subtly suggest that perhaps she wants to be boned--in the butt. Despite a woman's natural inclination towards boners, most women will find this proposition too direct and will not inquire further, If a guy inquires, simply use the following two step procedure to diffuse the situation.
Step 1: Tell him that it just happens to be the way your pants bunch up in the crotch area when you sit down. It's not unusual for pants to do this, so it's a perfectly reasonable explanation.
Step 2: Run."
For all this and more, check out The Alphabet of Manliness!