I think it is hard to make distinctions because what is spiritual is intangible and very difficult to describe, if you can describe it at all.
The sensual is a little easier because you feel and perceive but ultimately in the end the goal is to integrate the sensual and spiritual in perfect alignment with the will of God. Both are essential to the human experience and our relationship with God.
I can guess that the sensual is a number of things such as being able to “see” God working in your life and feel Him present during prayer or even other times. Often there is a “high” of sorts from the practice of spiritual things. I think of marriage when you are infatuated with your beloved and it gives you such a great feeling to be in love. The feeling is NOT actually love. The love is in its infancy and getting much TLC from heaven, a lot of floods of passion, even heart flutters, you can devote a lot of time to prayer because it is rather enjoyable. All good stuff.
But the chemicals die down and the senses aren’t as stimulated, you might not feel as eager to devote so much time and attention because there isn’t much in it for YOU. But here is where love is made pure and real. You stop seeking an experience rather than sharing or giving an experience.
I’d say the spiritual is that connection that you don’t really “feel” but you just “know.” It’s something deeper and so real you take it for granted. Kind of like air. Now we don’t really perceive air but if you didn’t have it, you would suddenly become aware of the lack of it’s presence. Going through the dark night of the soul would be like climbing to the top of a mountain where the air gets thinner and harder to breath until you get acclimated.
That’s my shot at it!