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There does not seem to be a concept in Pony able to generate something between "wet" and "cum", more similar to the concept of "suggestive fluid". The idea to be able to generate a wet or clear liquid effect without making the entire character looking soaked, or having an obvious white liquid. You can use this to target specific areas of the body or even objects. See the example images.
Tag: slimy
Usage: "slimy [target]". Examples: slimy ass, slimy breasts, slimy penis, slimy tentacles, etc. Some work better than others. You can also use "slimy string" or "slimy trail". You can add in the negative "wet" for better control of the effect.
Recommended quality tags: score_9, score_8_up, score_7_up, score_6_up. Optional: source_anime
Recommended negative tags: score_4, score_5. Optional: 3d, lips, realistic
Note that the end result can be affected by the base model, other loras, and prompt complexity.