Oh, she is. The instant he starts to shift she's bracing herself, pulling up until she knows how far he's going, and then he slides that finger inside her.

"Ohh, Gene."

She rests her forehead against his shoulder, taking a moment to catch her breath. Her hand slides around his erection, fondling him almost absently. Of course, the goodly portion of her attention is on his hand, and the pleasant friction starting to bundle in her belly like catching fireflies in a jar.