Rebecca Black Had Loads of Gay Sex to Cope With Tough Katy Perry Tour

Rebecca Black says the grind of touring with Katy Perry nearly broke her -- so she coped the only way she knew how ... by diving headfirst into a whole lotta gay sex.

Yep, the singer let off some serious steam by getting down and dirty on the regular -- calling it a blessing to always have steamy nights to look forward to with her mystery GF ... whose identity she’s keeping strictly under wraps.

Rebecca broke it down for PEOPLE -- the last few months have been chaos ... opening for Katy's "Lifetimes" tour, headlining her own tour in the spring, dropping her "Salvation" project in Feb, and squeezing in DJ sets and festival gigs on top of it all.

As for Katy’s tour, Rebecca said the wildest part was realizing it takes more than a village to pull those shows off -- and stepping into venues packed with 10K-plus fans was straight-up overwhelming at first.

In the end, Rebecca said the madness smoothed out -- the shows became fun, and she ended up living it up twice over -- slaying arenas by night, and pulling encore performances in the bedroom with her GF.