Hậu môn tình dục biến cô ấy thành chủ

It may be a good idea to use your tongue to lick and explore her anal area, thereby increasing

her pleasure and stimulating her organs.

This technique is called anal lingus.

Now, you may begin to stretch the sphincter carefully and slowly.

For this, you'll need to apply lubrication to your finger to prevent any unpleasant friction.