The Tik Tok special effect you described is "Do you want to add onions", which is a popular special effect recently. This special effect is usually used in the process of making recipes or food, and there will be some humorous and exaggerated elements.

If you want to use this special effect, you can follow the following steps:

1. Open Tik Tok app and select the video to add special effects.

2. In the interface of shooting, editing or uploading video, find the "Special Effects" button, and then select "Edit" or "More".

3. Search for the special effects of "Do you want to add onions", which can usually be found under the category of "gourmet" or "funny".

4. Select special effects and apply them to your video. You can adjust parameters such as position, size and duration as needed.

5. Preview and save your video, and share it with friends or post it on the vibrato platform.

Please note that the use of Tik Tok special effects may be restricted by copyright, trademark or other laws and regulations. It is recommended that you abide by relevant laws, regulations and platform regulations to avoid infringing on the rights of others or being dealt with.