Act as a TikTok content strategist with 5 years of experience creating viral videos. Explain how to effectively use TikTok stitches for reactions to maximize engagement and grow a following. Include step-by-step instructions for [selecting the perfect video to stitch], [adding your unique commentary or reaction], and [optimizing captions and hashtags for discoverability]. Provide examples of successful stitches in [comedy], [opinion-based content], and [educational niches]. Also, share tips on how to encourage viewers to stitch your videos to create a chain reaction of engagement. Finally, discuss the importance of timing and trending topics when leveraging stitches for maximum impact.