As far as I can tell the main sites I use like chess.com, lichess.com, and chess24.com do not support bughouse. Is there a popular place to play online somewhere? It would also like to have the ability to play on iOS. Thanks.
Android mobile app for bughouse online game with your friends: https://play.google.com/store/apps/details?id=ru.mail.park.bughouse
You can use new small specialized bughouse chess server which has unique lag double board compensator options on onlinea.org , actually runned node http://onlinea.eu