It doesn't benefit either one of us if I were to fake it. My Man
couldn't learn what works
if I were to fake it, and we both would be subjected to dishonesty.
If I want sex "to end" we end it. We solve this problem by having me usually come first. I rarely ever come for the first time during PIV (most women don't come during PIV (intercourse)) so we use oral sex, toys, manual play, more oral sex, toy etc until I get where I need to be. On the occasion when I don't come, I know we'll work on it next time. But, most of the time, when I come, I have to during his giving me oral sex or while we're using a toy. If I come again during PIV (and we almost never start PIV until I've already had my first orgasm, either) it's a bonus.
I feel faking it would be like lying to him, and then we'd both be frustrated. We work through our issues and often find it's easier for me to come with less pressure, so he knows when to back off and use a toy for me to finish.
This is what works for us. Faking only teaches your partner bad habits and puts a wedge in the relationship.