I’m not sure, but I don’t think I’ve ever drawn Bulma with Goku before. However, I don’t think it’s out of character at all for the version of Bulma I’ve presented over the years to have slept with Goku since pretty early on, and so that’s where the idea for this answer comes from. Goku seems pretty complacent with this arrangement, though I think Vegeta’s a little less happy about it. Bulma gets what she wants, though, and right now it looks like she wants a double-stuffing of Saiya-jin.