Because I haven't posted anything in a while and don't know when I'll make a comic, here's some sketches of Jacob in some of his forms.
His personal favorite is the form at the bottom, but he is always out to seduce humans so he'll use the others as he sees fit. There's just a few things he can't change, which includes his voice and man-bits.
So the nice lady is having a voice like this [link]
(so he usually doesn't talk when female) and quite a surprise under the skirt.