Lawrence O'Donnell Grills Foster Friess On Aspirin Contraception Comment (VIDEO)

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Lawrence O'Donnell tried to wrap his head around Rick Santorum backer Foster Friess' highly controversial comments about birth control on Thursday's "Last Word."

Friess, a billionaire and the main donor to a super PAC aligned with Santorum, joked about women using aspirin as contraception in an interview with MSNBC's Andrea Mitchell on Thursday. "The gals put it between their knees and it wasn't that costly," he said. He has since apologized for making the off-color joke.

O'Donnell hosted Friess that night to find out exactly what what he had meant. Friess explained his remark as a bit of historical humor. "Back in my days, they didn't have the birth control pill," he said. "So to suggest that Bayer Aspirin a birth control was considered pretty ridiculous and quite funny."

The two disagreed on the availability of contraceptives. Friess argued that public health clinics distribute contraceptives, while O'Donnell answered that not all women have access to them. However, the interview remained surprisingly friendly.

When pressed by O'Donnell on whether he agreed with Santorum's personal beliefs on birth control, Friess explained that has "been blessed by contraceptives," and heralded their importance for women. However, he took issue with the government's recent ruling that mandates all employers to cover contraception for their workers.

"People can choose," he said. "That's what's so annoying about this idea that President Obama forcing people to do something that is against their religious beliefs."