I looked this up in the OED, expecting to find nada and instead was rewarded with a good laugh...

hottie/hotty
colloq.
A hot-water bottle.
1947 H. Walsh Fourth Point of Star xx. 102, I am going to+rub my feet with meth., then get into bed with a hotty. 1956 D. M. Davin Sullen Bell vi. 40 Get a hotty for yourself. 1960 V. Anderson Daughters of Divinity vi. 51 And show her where to fill her hotty? 1967 R. Harris All my Enemies xiii. 117 You look rotten, Jenny. At least have a hottie to clutch.

I suppose there could be some nexus to grab onto [cough] here, but hasn't it been used mostly in rap for a 'hot woman'?