Charles Xavier was a dirty old man

Charles Xavier's (Professor X) vast psionic powers enable him to manipulate the minds of others, warp perceptions to make himself seem invisible, project mental illusions, cause loss of particular memories or total amnesia, and induce pain or temporary mental and/or physical paralysis in others. Within close range, he can manipulate almost any number of minds for such simple feats.

After an exhausting career battling Magneto and others, Charles was tired and wanted to just let loose. He was surrounded by hot female mutants, not to mention he could easily drive into town and be surrounded by hot non-mutants.