Exposing the bottom card of a deck of playing cards is a common mistake made by inexperienced dealers during home poker games. For this reason, you should probably use a cut card which is placed under the bottom of the deck to prevent the bottom card from being seen. Cut cards are always used in casino's and you will sometimes see a dealer holding the deck upside-down, knowing that the bottom card cannot be seen through the cut card.
The common practice when using a cut card is to place the cut card on the poker table next to the recently shuffled deck of cards. The player who cuts the cards places a stack of cards from the full deck on top of the cut card. The dealer then places the remainder of the deck on top of the cards that have been cut and begins to deal.