The GRAPHITE STALLIONS, one of our city’s new startup companies, has teamed up with Artscape Youngplace on Shaw Street for 2-hour sketching parties. And what are they sketching? Nude, buff young men who are quite prepared to sit in a chilly studio while being committed to paper by fully dressed women artists.For novices interactive art instruction is available, and the sessions are filled with music. The co-founders have art backgrounds – Martha Malloy works in art design, and Kirstin Bojanowski is an abstract painter. “It’s all about celebrating beauty and somebody’s body,” said Malloy.