I started using Neutrogena Liquid several years ago. 2 long squirts per quart is fine, but sometimes, if I haven't taken one in a while, I'll double that. I used to use Ivory, but found I couldn't hold it as long I'd really hoped to - the cramps became almost frightening. But since Neutrogena is PH neutral, even with a fairly high soap to water ratio, the cramps are minimal. Three quarts of a fairly dense solution of Neutrogena and water can be held quite comfortably for more than five minutes. For a longer hold, use a little less soap. But if you're a newbie, start with 2 quarts of water, 2 good squirts of Neutrogena liquid soap (fill the bag about 1/4 full, add the soap and then fill the bag to the top), keep the bag about 24-30 inches above entry and relax. You should be able to take it all. Once you've achieved that, you're on your way to a variety of pleasurable combinations and fills.