Have them make out

You lean back against the desk and let Julia take the lead as she seems quite eager to initiate her friend in the secret workings of GloMa.

"Part of becoming a lady is learning about... well, sex. I know it seems a little weird that it's so... hands-on, but that's the best way to learn, right?"

She brushes her fingers over Lucy's cheek.

"Besides, that means the teachers don't mind if we... experiment."

She leans forward slowly. Lucy hesitates, possibly because of the string of sperm across Julia's face, but then she meets her friend in a soft, tender kiss. The girls entwine their fingers while kissing, but soon their hands begin to wander. It seems they forget about your presence completely as they kiss more and more eagerly, pulling their jackets off and touching each other through their school blouses.