So fat that traditional self-pleasuring is impossible (too fat to reach around belly, thighs and fat pad.)

My own personal fantasy that could cause issues; you finally become that 700lb blob you've always wanted, but your spouse/mutual gainer is also a 700lb blob and you can't find a release since sex is impossible... thoughts?

Been juggling the idea of whether I should commit to a 50-75lb. gain or a full 100lb. and if it's worth following my fantasy gain of 175lb. Having trouble rising above my peak of 300lbs. as well. Tips or advice?