I want a character to be able to spit/spray from the mouth many different liquids created within the body.
Liquids would include a strong acid, flammable liquid, strong poison/nerve agent, a sticky glue like substance, and I am sure there will be more added at a later date. There may be different versions of each type.
The liquids would be spat/sprayed one at a time or combined if suitable. For example, the acid and the glue combined would create an attack like spitting spiders, but at other times having acid in the glue would not be helpful, so the character would need to be in control of bringing up which ever liquid they need.
I thought they would have individual glands for creating each specific liquid that can be easily released into the throat through some inner muscle control.
The problem with individual glands is it limits the number of chemical liquids the character can make and also maybe the volume able to be sprayed. I had thought either an over-active saliva gland or stomach acid could both dilute to control the chemicals strength and to add volume, but a single liquid for those purposes may not react well with all chemicals.
The ideal option would be a stomach that can create almost any chemical, but I cant think of a science-based mechanism for any chemical to be created instantly, and I don't want the character to be that powerful.
So my question is: other than a multiple glands system, is there a better way to achieve creating and spitting/spraying a variety of liquids?