You can do "I trade (username)" and it'll go through like a normal !trade command. Just watch out for people asking you to say it if you have a good stando.
Some idiot told me not to do that and when I did it send a trade to him. this was after the STW rework I TRADED OKC FOR STW and I was trading for STW before he came and that STW is gone bc I traded for kars