Another thing to note about a decompression is that on aircraft such as the A320 family, the 757 and 767, you will also start to smell burning just after the decent starts and people start putting on their oxygen masks... It is nothing to worry about, however, the oxygen is produced by chemical oxygen generators which get very hot, and over the months, dust builds up on them, and then burns when they get hot... Much like if you have had the central heating off all summer then the first time you switch it on for the winter, you get a slight "burning dust" smell... but it would be worse on the aircraft.

Also, you might well get a crew member in your lap. So, just make sure you squeeze them tight and don't let them go till they ask you too...