I'd always don't fake but do give gentle advice and encouragement. If they ignorance that or get stroppy well they will never be any good at sex, since we are all different and like different things or even the same things just done differently.
I have never faked. I never come by sex alone. I'm not built that way. I'm always (maybe too much) honest. "I won't come" I tell whoever is fucking me. If I want to come, I can always sort myself out. Please form an orderly queue to prove me otherwise, but in 26 years it hasn't happened yet.