I don't understand the phrase "don't be a pussy"

I don't understand the phrase "don't be a pussy"

Bi-Trans-Alliance: #Protecttransyouth Rally In Nyc At Stonewall (2/23/17)

🌜Rad-Ass Bitch🌛

🌜Rad-Ass Bitch🌛

🌜Rad-Ass Bitch🌛

🌜Rad-Ass Bitch🌛

Cruzfucker69: Third Base Is Me Asking If You Hate Me

🌜Rad-Ass Bitch🌛

🌜Rad-Ass Bitch🌛

Mygiantsainteverything: Emo Jimmy Was Great

Doobiedrewbie: 💜 Cleaned Two Of My Babies! 💚

Oh-Snap-Pro-Choice: Reginaeinferos: Therevenantrising: Reginaeinferos: Therevenantrising: Reginaeinferos: Nothing Is Going To Change. Americans Love Their Guns More Than They Love People And After Sandy Hook We Decided That Killing Over 20 Children

Ruinedchildhood: 😭😍😭😍😭😍😭😍