honestly maybe just avoid shaking hands the best you can, most people i feel don’t go right in for the handshake so you should be in the clear most of the time. when it’s unavoidable nobody would make a big deal of you saying you need to use the restroom as an excuse and it’s usually good timing when you meet someone new to like ask where a bathroom is or something anyway!

the more you give into washing your hands after you shake someone’s hands, the stronger ur ocd becomes. u can’t avoid it completely either. so just think to yourself “ i’m going to have to take the risk of what will happen if i don’t wash my hands” and try ur very better to lean off that compulsion. it’s definitely easier said than done.