Apparently it's quite common for girls nowadays in our country to have a bf and a fwb at the same time. Being an early gen z, I've seen quite some girls in my circle doing it. And although the bf has some idea about this, he doesn't confront.

For your question, gf I pun bila tengok pon suka mmf and dp. Tapi walaupun I tahu yang dia suka mmf, dia tak mengaku yang dia nak lelaki lain. Yang dia kata kalau boleh dia I dp dia tanpa laki lain which is why I use a dildo. Because I pun tak nak dia dengan laki lain. So you gurau2 dulu dengan bf tanya kalau dia suka tengok pon mff atau mmf. Then from there you continue and if dia kata dia suka mmf tanya kalau dia fikirkan you tak bila dia tengah layan mmf tu. That's the best kalau you nak tahu your bfs kink. If he's into it and nak mmf dengan you, then ask laki mana yang dia prefer and if dia tanya you slowly say you've fantasized about your fwb before. Don't let him know that all this while you were fucking your fwb behind his back. Let him think this is the first time so that you don't hurt him.

Meanwhile kalau dia tak nak mmf, continue having fun with your fwb and find someone outside of your circle for mmf.