I think that lyric is referring to the taste of woman (or even more metaphorically the taste of her personality the taste of her love, etc.). This particular taste is the idea that like any other taste the flavor is fleeting and you have a tendency to forget what that taste feels like when you haven't had it for a while. He has forgotten the taste and in doing so has cheated on this girl, and he wants to tell her what he has done, but as he says "As hard as it can be, it can feel so wrong" because even though you want to tell the truth, it can be so hard, especially the fear of loosing them. and the worst part is that he's destroyed the relationship because as the first lyric states
"Floating like a smoke ring, it cannot be regained, now it's touched, now its broken"
I think this song is about infidelity...
"The taste just slips away"
I think that lyric is referring to the taste of woman (or even more metaphorically the taste of her personality the taste of her love, etc.). This particular taste is the idea that like any other taste the flavor is fleeting and you have a tendency to forget what that taste feels like when you haven't had it for a while. He has forgotten the taste and in doing so has cheated on this girl, and he wants to tell her what he has done, but as he says "As hard as it can be, it can feel so wrong" because even though you want to tell the truth, it can be so hard, especially the fear of loosing them. and the worst part is that he's destroyed the relationship because as the first lyric states
"Floating like a smoke ring, it cannot be regained, now it's touched, now its broken"