I agree with a few on here, if you can throw your legs over your head and cum into your mouth, then that’s the easiest way. Unfortunately as I’ve got older I’m no longer flexible enough, but I’ve enjoyed doing it Iike that since my youth. Practised so much when I was younger, I managed to be able to lick the tip of my cock for 20 years.
Another way that works for me is, wear a flavoured condom, cum in it, but leave it on your cock to keep the cum warm, after a few minutes, you’ll feel horny enough and happily eat it. Just lower the tip to your mouth and bite the tip off it if the smell of your own cum puts you off.
Or tie off the full condom, rest it between your ass cheeks to keep it warm if your in bed at night, 30 minutes later, you’ll really feel like it, let just place the condom in your mouth and gentle bite through the condom, your cum will instantly fill your mouth well after you’ve originally cum. Sometimes I’ll still be horny enough to wank again while I bite through and swallow the first load.