"making it wider" and "tilting it into a female position" aren't the same thing - which is good news, because the former is unlikely on anyone past puberty, but the latter is basically just a matter of posture.

Personally, I found that HRT did make my butt bigger and shift my center of gravity enough that standing with my pelvis tilted more was both comfortable and natural (I have to try if I want to straighten up fully, and it's a strain), but I'd imagine that you could practice doing so until your muscles were familiar with that position and comfortable in it.