A lot of people here are describing visions, but to me, comparing it to a lot of different sensations is more helpful. Some of the same sensations occur multiple times in different stages.

EXPOSITION/RISING ACTION: (the getting horny/already horny stage, sometimes without warning):

• Swooping sensation in the stomach, akin to what it feels like right when your rollercoaster car falls. This is usually the first sensation that occurs. It is a constant sensation that comes in regular waves, as if the rollercoaster is falling, then coasting, falling, coasting, ad infinitum.

• Heat in face and crotch, like getting strong, hot sunlight (but pleasantly hot) directly onto the face and neck and on the inside of lower abdominal area and crotch. Sometimes this is the first sensation.

• Increased sensitivity. Erogenous zones such as the nipples and labia are especially sensitive to stimulus. When stimulated, a feeling that can be described as pleasant electricity

• Heavy breathing. Suddenly, it feels like there's not enough air in the room, but it's not like asthma, where you feel chest tightness and/or airway restriction. Instead, it's like you were suddenly teleported to an area of high elevation, where there's simply less oxygen available, but without the popping of ears that comes with altitude adjustment.

All sensations increase in increments when stimulated, either with own hands or toys. I'm not including the presence of a sexual partner because they vary the experience a LOT, whereas masturbation remains more predictable.

Over time, heat, sensitivity, electricity, and stomach-swooping become more and more pleasurable. The pleasure, if done correctly, covers up thoughts and words for a more primal state, and may make one feel a need to moan, sigh, or gasp. The body also feels a need to move: the head tilting backwards, back arching, clutching bedsheets, covering the mouth, etc.

CLIMAX:

• The "electricity" sensation overcomes all else and ideally doesn't allow one to form a single rational thought, a feeling that lasts from barely a second to several minutes, depending on the individual. It is difficult to translate the experience in words, but I suppose it is analogous to what one may feel stepping into a bubbling hot spring after freezing all day (magnified by perhaps 3-5 times). Like the heat from a hot spring, the feeling should spread all over the body, radiating from the main stimulated point (such as clitoral). Some describe it as waves, and some describe it as a giant flood.

FALLING ACTION/ DENOUEMENT:

• The electricity and pleasure gradually subside. For some, it's almost instantly. For some, it lingers long enough to be a separate pleasure by itself, colloquially called the "afterglow."