In a nutshell, cummings is writing about two interwoven things: the narrator's emotional connection to another person, and the metaphorical/metaphysical journey he takes. It is possible, even likely, that cummings is the narrator, and it is likely from the images (roses, and small hands) that the other person is a woman. Something in her look opens up the parts of him that have been closed up, and he's hypnotized by what he sees in her and her beauty.
For an extended discussion of this poem, reviewing its meaning stanza by stanza, see the Summary section of the enotes study guide:
try reading it a few times. it is an extremely simple poem.