Does anyone have any tips for singing and playing the bass at the same time?

First, start with a song that isn't too hard and then play it as simple as possible, mostly root notes if you can. Then, match the syllables of the song with the notes you're going to play. Play it slow, and eventually, you'll get better. It does take time, don't beat yourself up and have fun with it.

I too am a bass player and singer. What I do is I learn the bass part and the vocal part separately and then I put them together. This way, your fingers get used to the notes and rhythm you are playing so you don't have to think about it so much. Then you can focus on adding the vocal part.

Try to play and sing in ur head man, then when u feel like u got the singing and playing in ur head play the bass and sing one part of ur song out loud and pratice it over untill u get it down and then go on to the next part of ur song and so forth.

get a metronome and play the parts as it's written.

a metronome will do wonders while playing along with it.