It is pretty easy and cheap to just stick a bottling wand in the end of your picnic tapper. If you find a #2 cork, it should fit the bottling wand and can be adjusted to the height of the bottle you are filling. I often pump the carbonation up in my keg a day or so before filling (but that isn't necessary), then I bleed off most of the pressure before filling. Chill your bottles as cold as possible, then insert the wand into the tapper, open the spigot and start filling. I just push against the stopper with my thumb to slowly let out O2 as the bottle fills with my beer/wine/cider. When it is pretty much full, I pull out the wand and cap the bottle. It lasts a good week or so under decent pressure/carbonation.