The test kit provided by Family Tree DNA consists of several cotton "toothed" tip swabs and containers in which to place them after the sample is taken. Each swab is used to scrape the inside of your cheek for 60 seconds, allowing 3-4 hours between each swab. This feels much like using a toothbrush would feel. The swabs are then placed in a contained with fluid to keep bacteria from forming. The package of containers is then mailed back to Family Tree DNA.
The Family Tree DNA web site provides more details on the Test Kit, and Instructions on how it is used.