Have tried both together numerous times, yes.
It's definitely an interesting feeling, hard to describe.
It seems the usual body euphoria in terms of touch sensitivity, waves of tingling and warmth, etc are somewhat attenuated
Really don't give a fuck about ANYTHING though and most things are enjoyable.
Memory also goes to shit.. I've had plenty of times hanging out with people under this combo, sometimes even long conversations and hardly remember many specifics of what occured, just bits and pieces + a general picture of it all. Even when I'm talking it's weird.. it's like I can't consciously remember what I'm stating but everything still flows very eloquently. I actually came to a realization of how good my memory was when I was on phenibut, + inebriated via alcohol, and high from cannabis and dropping some serious knowledge for like 30mins-1 hour straight lol

like I couldn't consciously have a good flow of thoughts but the same level of nuanced erudition flowed eloquently as usual.
I'm also really loquacious with this combo.. even prolix at times.