S12E15 — The Donation Oscillation
The Big Bang Theory — Season 12, Episode 15.
Penny tries to seduce an abstaining Leonard to ruin his "donation" for her ex-boyfriend, Zack, and his wife, Marissa. Also, Wolowitz, Bernadette, Anu and Koothrappali turn Koothrappali's canceled bachelor party into a couple's trip.
View all episodes of The Big Bang Theory