Mars shows what a woman is attracted to in a man. Being with a man who is strong in her Mars element, or who makes close sextiles with her Mars, makes the relationship much easier, and increases sexual desire and compatibility. For a man, his Mars is part of his masculine nature, so it is best when his partner also relates well with this element.
Mars Trine Neptune
There is nothing to hold you within boundaries. You certainly have active imaginations, but Mars energies easily get tangled up in sexual or aggressive fantasies, or perhaps a bit of both. Your partner inspires creativity, maybe you can inspire him/her to bring some of this romance into the real world. Anyone for role playing? When the Mars person is trine the Neptune person it may be easier for him/her to do it in the head than in bed. Clarify some of your best dreams and wishes and put some real world energy into making them happen. You might be surprised how easy it is, and how much fun you can have.