With future perfect (F2) you jump to a point in the future, turn round and say some action is finished then. Actually a complicated thing and cumbersome and in most cases you can express the same idea much simpler without using F2. This tense existed in Latin and it was imitated by writers.
In current English usage, muse can refer in general to a person who inspires an artist, writer, or musician.
Muse (alprostadil) for Erectile Dysfunction: Creates only a soft erection; not enough for intercourse. I have mentally separated ejaculation from intercourse because what I primarily want is the sense of oneness with my mate. With a MUSE injection I feel a sort of pain, which also is felt in my ankles and lower legs.