In live casino or home poker games, when a poker player does not make the intended bet or raise in one smooth motion. For example, if a poker player wished to make a bet of $20, they cannot place $10 into the pot and then reach back to add another $10, as in this case only the first $10 bet will stand. However, this is permitted if the poker player verbally states "I bet twenty dollars." String bets can also be made verbally if a poker player states "I call x amount and I'll raise you x amount" as in this case only the call will stand as this was the action first stated. The statement should simply made as "I'll raise you x amount" as the call is obviously included in this declaration. This poker rule exists to prevent unfair manipulation of a situation and to ensure the other poker players know for certain what action is being taken and cannot be tricked into reacting too early and therefore give away vital information.
An unethical and often illegal means of raising whereby a player puts a call-size stack of chips into the pot and, after observing the reactions of the players, then goes back to his stack and puts out more.