Lust only makes a cameo in "Persephone, Falling," but it's really the background for a lot of the psychology of the poem. We're talking about a girl coming of age, here. There are bound to be some desires at play. Hades is mostly painted as a lusty monster, but there are a few hints that Persephone is perhaps feeling a wee bit frisky, too.
Hades is scary sexy—he represents the intimidating appeal of lust to the young Persephone.
If we read the last two lines literally, it's just a rehash of a tired old wives' tale: that fleshly desires or lust will ultimately lead to doom.