Try that Wal-Mart toy a few posts up.funny I’ve never tried under the tub faucet just the shower head which doesn’t work well, inflator mechanism gets in the way even with valve open... I’ll try it next time. thanks
https://www.walmart.com/ip/Plumb-Craft-Waxman-7653700B-Versa-Bath-Spray/15389318
Slide the rubber cone onto the faucet, cut the shower thingy off the hose, and stick the hose in the inflator mouthpiece while pushing the deflate button. Should fill your bcd pretty fast.