Pleasure is a state, in which you feel good and enjoy what you are doing. Usually, it does not last long, as the attention moves to other subjects, and because life is such that you have always other things to do, like work, cleaning the house, driving somewhere, interacting with other people, etc.
When you eat some delicious food you derive pleasure from it, but the pleasure doesn’t last for long, since you cannot go on eating indefinitely, you finish eating the food on your plate and the sensation of pleasure wears off after a while. You may enjoy watching a movie, but the movie lasts for a certain amount of minutes. When you read a book that you enjoy reading, ultimately, you reach the last page.
As you see, all pleasure is time limited.
Pleasure is usually awakened by external stimuli, and is largely physical, involving the five senses, like the smell of good food or its taste, a pleasant breeze, or of the sight and physical contact of a certain person. You can also derive pleasure from reading a book or daydreaming.
Pleasure is emotional in nature, while happiness is a state beyond the emotions and even beyond the mind. In pleasure the emotions and feelings are active. While in a state of happiness there is calmness and peace.
Though happiness is similar to pleasure in some respects, yet it is different.
Happiness does not depend on external stimuli, since it comes from within, though quite often, it seems as if the source is external.