cling like a limpet

cling / stick / hang on / hold on like a limpet (to sth/sb) AND (stick like a limpet (to sth)) — ≈ не отходить ни на шаг от кого-л.; ≈ пристать как банный лист; ≈прилипнуть как банный лист; ≈ быть надоедливым, надоедать; прицепиться; приставать

Example 1: On Anna's first morning at Pricewell's, she caught the early bus with Luke and Flora. Flora clung to her, like a limpet. (Joanna Trollope, The rector's wife)

Example 2: He latched on to this idea like a limpet.

Example 3: Strong arms enfolded her. She screamed again. "Annabelle? What the devil!" She almost fainted with relief. "Gerry, is it you?" She saw that it was Lord Temple, and clung to him like a limpet. "Someone tried to murder me," she sobbed out. It took several minutes to calm her. Lord Temple patiently listened to her incoherent explanation, and by dint of careful questioning got the story out of her. (Elizabeth Thornton, The Worldly Widow, 1990)

see also
[stick like a bur]
[mustard plaster]

[on one's heels]