My japanese friend only speaks english with me, how could we switch naturally ?

Hey everyone, so here's the deal.

I have a japanese friend, who speaks very well english. My japanese is not as good as her proficiency in english, so we only talk in english and never in japanese since this would be awkward I guess.

Have any of you experienced something similar, and achieved to ask in some way to (naturally) start adding japanese too during conversation or whatever ? Doesn't necessarily have to be in conversation (whatever other aspect of learning too is welcome), as long as I could benefit a bit of knowing a japanese native speaker.

I'd be happy to exercice my japanese with this friend but I cannot find any way to switch to japanese or ask for it in whatever other way, without making it awkward.