[…] and now they rangeBusily seeking with a continual change (6-7)
Apparently, these girls are quite promiscuous. They're constantly seeking "continual change," which we take to mean that they're looking for new men to sleep with. Later in the poem, the speaker will talk about one particular woman's love of "newfangleness." Our speaker seems to think that women are nothing if not fickle in love.
When her loose gown from her shoulders did fall,And she me caught in her arms long and small (11-12)
The tables have turned, that's for sure. Here the speaker depicts the woman as the dominant sexual partner. She catches him just like a trap or a hunter would an animal, which is, shall we say, less than romantic.