Yep! Love a finger up my hole while I’m getting a handjob / blowjob. My ex used to do it during sex while in missionary / reverse cowgirl too.
 
Sure!
All sorts of anal play is very pleasurable! From rimming, to finger touching, inserting a finger (or two!) during a handjob or blowjob, prostate massaging, and pegging! All these acts give a very different kind of pleasure, and can definitely help to reach a stronger type of orgasm!