1 This iconography is Devi Chhinnamasta.
She is the "self-beheading" fierce goddess.
2. The two standing are Devi Chhinnamasta's attendants: Dakini and Varnini.
"Both of the attendants – Dakini to her left and Varnini to her right – are depicted nude, with matted or dishevelled hair, three-eyed, full-breasted, wearing the serpentine sacred thread and the mundamala, and carrying the skull-bowl in the left hand and the knife in the right. Sometimes, the attendants also hold severed heads (not their own). While Dakini is fair, Varnini is red-complexioned."
3. The couple making love:
With her right leg held straight and her left leg bent a little (the pratyalidhastance), Chhinnamastastands in a fighting posture on the love-deity couple of Kamadeva(Kama) – a symbol of sexual lust – and his wife Rati, who are engaged in copulation with the latter usually on the top (viparita-ratisex position). Kamadevais generally blue-complexioned, while Ratiis white. Below the couple is a lotus with an inverted triangle, and in the background is a cremation ground.
You can read a very good article on Devi Chhinnamastaat Wikipedia:
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Chhinnamasta being one of the Ten Mahavidyas: