Viagra isn't something that requires consent

Viagra isn't something that requires consent.
It's a biological effect.

As for your statement that no woman can rape you--WRONG.

When I was a rape crisis counsellor, we had a pair of women stalking men who were jogging in the parks of Baltimore. One held a knife to the guy's throat , while the other got him hard (it's an adrenaline reaction; it's why men often have erections in battle or other stress situations), and tightened a cock ring, and raped him. Then they changed places. The men were as traumatized as any women victims, perhaps more so because it was a WOMAN who had done it.

You can also be raped anally. One of my friends, a Domme, got a call forma male sub who had met two Dommes online and was meeting them for dinner. He was careful to ask for ID--but it turned out to be phoney as were the names they gave him--but he didn’t' arrange for a safe call that had to be made at a certain time or the friend would call the cops. While he went to the bathroom at the restaurant, they slipped rophynol in his drink. When he became dizzy and disoriented, they suggested he come back tot heir place and take a nap. He agreed. He came to tied to a steel frame, with a large dildo in his rectum, a cock ring around his penis, and being beaten a lot harder than he would have consented to be. He passed out again, cane to in his car, which was no longer at the restaurant but somewhere he didn't recognize. He called my friend who told him to get to the ER. He had anal tears and his penis was bruised and raw. Lots of bruises and welts, even a couple of places where the single tail had torn the skin.

It could happen to you.