Some other things to do
Become dominant (sisters love that )
Maybe call em a whore ( some chicks are into it )
Spit in there mouths ( very little chicks are into this but ugh who knows )
Spank em ( Some chicks are into that to )
Exhibitionism ( that's hot sis ) you could do anything front fucking in public areas to touching yourself in front of them (that's hot to sis)
Fuck in a church don't question it just do it
Vibrators are cool just a hint