How to create a swash underline words?

Hi all, i am a beginner in glyphs app and i was wondering how can i create a swash underline words like the picture below? I can’t seem to find any information or tutroial regarding this. Thanks!


I don’t think I understand the question. You open a glyph and draw it? If you want it to appear only under a certain word, consider making a ligature from the whole word, e.g. A_u_s_t_r_a_l_i_a for this example.

Or do you mean the OT feature code for making a swash underline appear under certain words?