The only U.S.-based company producing something like that is maybe Kink.com? They have lot of TS and bi/gay content. Sometimes they have pissing but its rare I think or disguised as squirting? I haven't viewed their content in long time and when I did I never subscribed to their TS or bi sites. However, occasional in femdom stapon sites "Men In Pain" and "Divine Bitches" they would sometimes cross that line and a scene might involve some bi action. Try searching their site.
The foreign companies don't have obscenity restrictions like U.S. so they can do everything. Well I know John Thompson used to before they cracked down on his GGG and 666 movies. But those were straight porn with a lot pissing though. If you want TS and bi action with pissing you have to do some digging thru foreign content. I would start by searching tube sites for such scenes then look for comments, tags, and watermarks stating which sites that clip came from. For example, I once saw clips on tube sites of brazilian TS pissing on guy which were actually produced by site called ShemalePunishers.com. Try finding more like that or sites similar to that on in content. For example, goto adult review sites like RabbitReviews.com enter ShemalePunishers.com and see if they reference similar sites or try Google etc.
The old school euro companies like Magma might have old titles featuring that type of extreme content also. But I think your best bet is online download sites for such an extreme niche.
BTW I have to say its rare to find a woman into that type of extreme content. I'd be scared to even suggest to my gf that we watch something so extreme ... assuming I was into that. Would be interested to hear how you first brought it up and about her initial reaction. Just curious. I once showed my gf a GGG movie (not even 666) and she looked at me like was crazy. ;-)
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