When using the engineering trinkets such as the Ultrasafe Transporter: Toshley's Station and the Dimensional Ripper: Area 52, you sometimes receive a debuff ranging from changing you into another race, making you bigger, making you golden, making you shadowy, and more.
If you get a debuff, equip another tinket in place of Engineering teleporter, then log off outside of a city or inn, anywhere that you are not rested.
Once you log in 3 hours or more later, the trinket will have cooldown and you can then equip it and reuse it to get another debuff and stack it.
Also, with a few of the debuffs such as Soul split good and evil, and the one that says you feel larger, these all enlarge your character. You can actually get rid of these debuffs by enlarging yourself twice more. I did this by drinking Winterfall Firewater, then in Warsong Gulch, picking up the Berserker buff. I grew so big that it reset me to normal size and removed the debuff.